An integrated retail operating framework
A connected operating model from assortment intent to executable stock policy.
RETAIL MERCHANDISE MANAGEMENT PAPER
Financial targets, assortment architecture, breadth, depth, store ranging, lifecycle, receipts and open-to-buy
Purpose A high-level operating design for translating customer demand and financial objectives into an executable apparel assortment by class, channel, store cluster, style, color, size and forward retail week. |
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Cybex Retail AI & Analytics Advisory
August 2026 | Illustrative design paper
A Merchandise Assortment Plan, or MAP, defines what the retailer intends to sell, where it will be ranged, when it will arrive, how much depth it will receive and how the investment will achieve sales, gross margin, service and turnover objectives. It connects the financial merchandise plan to the style-color-size decisions that purchasing and allocation must execute.
Core principle Plan the customer offer and its economics together. Breadth, depth, timing, price, margin, presentation, replenishment and exit must reconcile to one approved demand, receipt and inventory plan. |
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Financial envelope: sales, gross margin, markdown, receipts, stock investment and inventory productivity.
Assortment architecture: roles, choice counts, price points, brands, attributes, colors and size coverage.
Market localization: channel, climate, store cluster, capacity, customer profile and local demand.
Time phasing: launch, build, peak, replenishment, winddown and exit by forward retail week.
Execution: initial buy, chase reserve, receipt windows, DC allocation and exception management.
| Companion paper | Contribution to MAP |
|---|---|
| Apparel Stock Forecast | Supplies normalized, seasonal, forward-week demand and confidence. |
| Apparel Size & Color Management | Translates choices into color shares, size curves and constrained runs. |
| Retail Stock Optimization & Optimum Stock | Sets service, safety-stock, WOS and investment policies after ranging. |
Table 1. MAP coordinates the commercial plan; the companion modules supply detailed operating logic.
Top-down targets and constraints flow right to left; bottom-up choices, productivity and feasibility flow left to right.
Figure 1. MAP requires top-down financial control and bottom-up choice-level feasibility.
Set enterprise and category financial targets by channel and time period.
Translate demand into assortment roles, choice counts, price points and planned depth.
Range choices to clusters and stores using eligibility, demand, capacity and strategic rules.
Build the initial and replenishment receipt plan within lead-time and open-to-buy constraints.
Reconcile bottom-up style-color-size totals to approved sales, margin, receipt and stock plans.
Approve a version, execute it, then reforecast and govern exceptions in-season.
Operating output An approved MAP version should identify the merchandise hierarchy, market scope, forward weeks, financial targets, assortment roles, ranged choices, unit depth, receipt timing, store participation, scenario and owner. |
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The merchandise hierarchy provides financial control; the choice hierarchy provides execution. Planning must support aggregation and drill-down without confusing a style, a style-color choice and an inventory SKU.
| Level | Example | Primary MAP decision |
|---|---|---|
| Enterprise / channel | Retail, ecommerce, wholesale | Investment, sales and margin envelope |
| Department / class | Women / knitwear | Financial targets and assortment role mix |
| Subclass / attribute | Cardigans / cotton / opening price | Choice count, price point and attribute gaps |
| Style | Rib cardigan | Design choice, lifecycle and supplier commitment |
| Style-color choice | Rib cardigan - navy | Color breadth, initial depth and store participation |
| SKU | Rib cardigan - navy - M | Size demand, purchasing and allocation |
| Location / cluster | Urban A cluster / Store 101 | Ranging, capacity and localized depth |
| Forward retail week | Launch week through exit | Sales, receipts, inventory and action timing |
Table 2. Recommended hierarchy and the decision governed at each level.
| Record | Suggested grain | Core measures |
|---|---|---|
| Financial MAP | Version x week/month x channel x class | Sales, units, GM, markdown, receipts, BOM/EOM stock, turns |
| Assortment architecture | Version x season x cluster x class x role | Styles, colors, choices, price points, depth and capacity |
| Choice plan | Version x style-color x cluster | Ranged flag, launch/exit, initial depth, forecast and confidence |
| SKU plan | Version x SKU x cluster/store x forward week | Demand, receipts, target stock, allocation need and projected EOH |
Table 3. Separate records preserve financial control while enabling executable detail.
Figure 2. A time-phased plan identifies receipt needs, peaks, winddown and terminal-stock exposure.
| Measure | Definition / formula | MAP use |
|---|---|---|
| Net sales | Gross sales less returns and discounts, using the retailer's governed definition | Demand and revenue target |
| Gross margin | Net sales - cost of sales; GM% = GM / net sales | Profit and vendor / price-point balance |
| Markdown | Planned permanent and promotional price reduction | Exit cost and demand shaping |
| Receipts | Merchandise received in the planning period | Supply and cash commitment |
| EOM stock | BOM stock + receipts - sales - markdowns +/- adjustments, at consistent retail basis | Ending investment and exit risk |
| Inventory turns | Annualized cost of sales / average inventory at cost | Inventory productivity |
| Sell-through | Cumulative unit sales / (unit sales + ending on hand) | Lifecycle productivity |
Table 4. Core MAP financial measures; valuation bases must remain consistent.
Financial discipline Do not sum monthly EOM stock as though it were flow. Use average inventory, ending inventory, turns, WOS and sell-through to evaluate stock productivity. |
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Figure 3. Core choices normally receive deeper stock; fashion, test and long-tail choices require controlled depth.
Breadth is the number of customer-visible choices. Depth is the inventory committed behind each choice. In apparel, a choice commonly means style-color; the SKU count expands further through sizes and locations.
| Assortment role | Breadth posture | Depth posture | Typical treatment |
|---|---|---|---|
| Core / carryover | Narrow to moderate | Deep | High participation, replenishment and service protection |
| Proven seasonal | Moderate | Moderate to deep | Time-phased receipts and early chase |
| Fashion / key trend | Moderate to broad | Controlled | Short lifecycle, confidence-based depth |
| Test / capsule | Very narrow | Shallow | Limited clusters; explicit learning objective |
| Long tail / extended | Broad selectively | Very shallow | Digital or hub inventory; store access through network |
| Exit | Contracting | No new depth | Transfer, markdown and assortment removal |
Table 5. Illustrative breadth-depth policy by assortment role.
Choice economics Each additional style-color choice creates presentation, size-run, safety-stock, operational and markdown cost. Add breadth only when incremental demand and margin exceed the fragmentation cost. |
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| Core | Proven seasonal | Key fashion | Extended colour | Test | Long tail | |
|---|---|---|---|---|---|---|
| A cluster | 100% | 100% | 100% | 85% | 60% | 35% |
| B cluster | 100% | 100% | 90% | 65% | 35% | 15% |
| C cluster | 100% | 90% | 70% | 40% | 15% | 5% |
| Digital / hub | 100% | 100% | 100% | 100% | 85% | 70% |
Figure 4. A range matrix controls where choices are eligible before depth and allocation are calculated.
Store clustering reduces noise and gives merchants an understandable way to localize the assortment. A store may inherit its cluster range and then receive governed overrides for climate, local demand, strategic role, capacity or fulfilment capability.
| Range control | Application |
|---|---|
| Store / cluster ABC | Prioritizes productive or strategic locations without assuming every A store needs every choice. |
| Store index | Scales demand and depth relative to the normalized average eligible store. |
| Capacity | Limits active styles, color choices, SKU facings and units. |
| Climate / market | Controls seasonal timing, fabric, color and localized attributes. |
| Fulfilment role | Distinguishes selling store, showroom, hub and digital inventory. |
| Override | Requires reason, owner, expiry and expected outcome. |
Table 6. Range eligibility precedes purchasing and allocation.
Capacity rule When space is constrained, protect productive core choices, highest-selling colors and locally relevant sizes before adding lower-confidence breadth. |
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Figure 5. Lifecycle determines when receipts are useful and when additional stock becomes exit exposure.
| Phase | MAP decision | Inventory posture |
|---|---|---|
| Pre-season / commit | Approve choices, total demand, supplier capacity and initial receipt | Build only enough to support launch and lead-time risk |
| Launch | Measure availability, adoption, color and size response | Protect presentation; do not overreact to first-day noise |
| Build / peak | Release chase, replenish winners and rebalance stores | Use updated forecast and service policy |
| Mature | Reduce open commitment and review slow choices | Hold productive depth; release excess |
| Winddown | Shorten range, stop replenishment and consolidate stock | Sell through by exit; avoid restoring full runs |
| Exit | Markdown, transfer, return or remove | No safety stock after sellable life |
Table 7. Lifecycle-specific MAP controls.
Commit early only for demand that cannot be served through later receipts. Reserve flexible capacity for forecast error and early selling evidence. Long lead-time goods require earlier decisions and a larger scenario envelope; short lead-time goods can use chase replenishment to reduce initial risk.
Terminal-stock rule A plan is incomplete unless projected ending stock is visible through the exit week. Remaining units become transfer, markdown, return-to-vendor or carryover exposure. |
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Figure 6. Productivity typically concentrates in a smaller set of choices; ABC helps prioritize service and depth.
Choice productivity should influence depth, participation and replenishment, but it should not be the only design input. Strategic brands, opening price points, visual statements, new concepts and destination items may require controlled overrides.
| Class | Illustrative contribution | MAP treatment |
|---|---|---|
| A | First 85% of governed sales or margin contribution | Protect availability, broadest justified participation and chase capacity |
| B | Next 10% | Balanced participation, depth and replenishment |
| C | Final 5% | Selective range, shallow depth or network availability |
| Strategic override | Outside normal rank | Explicit role, investment cap, owner and test period |
| Exit | Lifecycle override | No new buy; consolidate and clear |
Table 8. Cybex 85/10/5 ABC convention applied to assortment choices.
Minimum expected sales and margin per choice
Minimum weeks at full-price selling before evaluation
Maximum inventory and markdown exposure per test
Minimum presentation and complete-run requirement
Capacity and cannibalization test before adding breadth
MAP approves the style-color choices and the market participation. The detailed size curve and color-size stock policy then translate each approved choice into SKU demand, purchase quantities and store allocation. This prevents financial choice counts from hiding unproductive colors or broken core sizes.
| Planning layer | MAP responsibility | Detailed operating module |
|---|---|---|
| Style | Role, lifecycle, price, total demand and supplier | Forecast and purchasing plan |
| Color | Choice approval, share, participation and initial depth | Color WOS, forecast and lifecycle |
| Size | Run eligibility, curve source and presentation minimum | Store / cluster size index and safety floor |
| Store / cluster | Range, capacity, demand index and fulfilment role | Allocation, replenishment and transfer |
| Forward week | Launch, receipt, replenishment and exit windows | Forecast, stock projection and WOS |
Table 9. MAP owns the commercial choice; companion modules provide SKU-level operating logic.
| Color role | Share | Store participation | Size run | Initial posture |
|---|---|---|---|---|
| Core navy | 34% | A/B/C + digital | XXS-XXL | Full curve; deepest depth |
| Core black | 28% | A/B/C + digital | XS-XXL | Full commercial curve |
| Seasonal green | 18% | A/B + digital | XS-XL | Shortened tail sizes |
| Fashion coral | 12% | A + selected B | S-XL | Controlled test depth |
| Extended cream | 8% | Digital / hub | XS-XXL | Network availability |
Table 10. Illustrative choice plan; percentages and runs are examples only.
Control total Color shares reconcile to 100% of the style demand before rounding. Size indices reconcile to 100% within each color and destination segment. Purchase and allocation rounding must preserve the approved total or record the variance. |
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Figure 7. Open-to-buy is the uncommitted portion of the approved receipt plan after existing stock and orders.
The MAP defines the receipt need; merchandise purchasing converts that need into supplier commitments. Open-to-buy, or OTB, protects the approved financial envelope while allowing merchants to redirect uncommitted investment as forecasts change.
| Calculation | Illustrative formula |
|---|---|
| Planned purchases at retail | Planned sales + planned markdowns + target EOM stock - planned BOM stock |
| Open-to-buy at retail | Planned purchases - approved on-order receipts - other committed receipts |
| Open-to-buy at cost | Retail OTB x planned cost complement, or calculate directly at cost |
| Unit buy need | Forward demand + safety / presentation stock - usable inventory position |
| Executable order | Unit need constrained by pack, MOQ, supplier capacity, timing, cash and lifecycle |
Table 11. Core receipt and OTB relationships; use consistent valuation and timing.
Commitment strategy Separate the initial committed buy, optional capacity, chase reserve and exit cancellation window. The plan should show how much investment remains flexible and when that flexibility expires. |
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Figure 8. Scenarios make opportunity and commitment risk visible before purchase decisions are fixed.
| Scenario | Use | Merchandise response |
|---|---|---|
| Base | Most likely governed forecast | Approve core plan and normal service targets |
| Upside | Higher adoption, event response or stronger traffic | Reserve chase capacity and prioritize A choices |
| Downside | Slower demand, delay or weaker price response | Reduce optional receipts and breadth; protect exit |
| Supply-constrained | Vendor, DC or logistics limits | Allocate by served margin, service gap and strategic role |
| Capacity-constrained | Store space or fixture limits | Protect core productivity; use hub / digital access for tail |
Table 12. Scenarios should identify the decision, not merely display alternate numbers.
Protect safety, legal and contractual requirements.
Protect high-value customer service for approved A choices.
Preserve presentation and complete-run requirements where economically justified.
Use transfers and network availability before incremental buying when feasible.
Release or exit low-confidence breadth before cutting productive core depth.
Actual sales, availability, margin, turns and markdowns recalibrate the next plan.
Figure 9. MAP is the coordinating commercial layer across the companion planning and stock processes.
| Interface | MAP sends | MAP receives |
|---|---|---|
| Apparel Stock Forecast | Approved scope, lifecycle, scenario and hierarchy totals | Forward demand, confidence, seasonality and reforecast |
| Merchandise Purchasing | Style-color-size receipt need, window, commitment type and OTB | Supplier feasibility, MOQ, packs, due dates, cost and commitment |
| DC Allocation | Range, launch, cluster participation, priority and destination rules | Available supply, allocation outcome, shortages and residual stock |
| Size & Color Management | Approved choices, color shares, run policy and participation | Size curve, color-size WOS, broken-run and constrained-depth result |
| Stock Optimization | Lifecycle, service segment and assortment role | Safety stock, WOS band, transfer and excess recommendations |
Table 13. Required information exchange across the merchandise-management series.
Single-version rule The approved MAP, selected forecast, purchase commitments and allocation run should carry compatible version and effective-date identifiers. Differences must be visible as governed variances, not hidden reconciliations. |
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Assume a 26-week women's knitwear plan for three store clusters plus digital. The forecast supports 48 style-color choices. The financial envelope allows an initial commitment plus a chase reserve, while store capacity limits the amount of fashion and extended color placed locally.
| Step | Illustrative decision | Result |
|---|---|---|
| 1. Financial envelope | Planned net sales $420,000; GM target 58%; markdown provision $35,000 | Approved category targets |
| 2. Architecture | 24 styles, 48 style-color choices across core, seasonal, fashion and test roles | Choice-count plan |
| 3. Market range | A cluster 100%; B 78%; C 54%; digital 100% of eligible choices | Range matrix |
| 4. Depth | 5,400 initial units plus 3,000 units reserved for chase | Commitment strategy |
| 5. Color / size | Color shares and cluster size curves reconcile to each choice total | SKU purchase need |
| 6. Purchasing | Receipt windows, packs, MOQ and supplier capacity applied | Executable orders |
| 7. Allocation | Range x store index x color share x size index; subtract local stock | SKU-store allocation |
| 8. In-season | Reforecast, release chase, transfer excess and shorten winddown runs | Closed-loop actions |
Table 14. Illustrative MAP decision chain; all values are examples.
Choice and SKU demand reconcile to the class / channel financial plan.
Store-cluster participation reconciles to capacity and presentation limits.
Initial plus chase commitments do not exceed approved receipt and OTB limits.
Allocated units do not exceed available-to-allocate supply.
Projected stock after exit is explicitly valued as carryover or markdown exposure.
Decision outcome The MAP approves the customer offer and the investment envelope. Purchasing and allocation may constrain execution, but they must return the variance so merchants can change breadth, depth, timing or service deliberately. |
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MAP should be versioned, merchant-owned and transparent. Approved targets, model recommendations, merchant overrides and executed commitments remain separate so the retailer can measure where value was created or lost.
| Perspective | Measures |
|---|---|
| Customer / demand | In-stock, complete color-size availability, forecast error, served demand and substitution |
| Assortment | Choice count, active style-color count, participation, sales per choice and attribute gaps |
| Financial | Net sales, GM$, GM%, markdown, receipts, OTB, average inventory, turns and GMROI |
| Lifecycle | Sell-through, weeks to peak, chase rate, terminal stock and exit-date adherence |
| Execution | On-time receipts, PO variance, allocation fill, transfer rate and recommendation acceptance |
| Governance | Override frequency, value add, reason, owner, approval and expiry |
Table 15. Balanced MAP scorecard.
| Cadence | Primary focus | Decision |
|---|---|---|
| Season / pre-season | Financial plan, architecture, range and commitment | Approve MAP version |
| Monthly | Class / channel outlook, receipts, stock and OTB | Rebalance investment |
| Weekly in-season | Forecast, service, winners, slow choices and capacity | Chase, hold, transfer or exit |
| Post-season | Accuracy, sell-through, margin, turns and override value | Recalibrate parameters and roles |
Table 16. Review decisions at the cadence where they remain actionable.
Governance rule Every override records the original recommendation, new value, reason, owner, approval status, effective weeks and expected outcome. Post-season review measures whether the override added value. |
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| Phase | Capability | Outcome |
|---|---|---|
| 1. Financial MAP | Versioned sales, margin, markdown, receipt and stock plan | One approved financial envelope |
| 2. Architecture | Roles, choice counts, price points, clusters, range and capacity | Visible breadth and depth decisions |
| 3. Choice / SKU plan | Forecast, color share, size curve, receipt and allocation need | Executable detail |
| 4. Scenario + OTB | Base/upside/downside, commitment types and open-to-buy | Controlled flexibility |
| 5. Closed loop | In-season actions, KPIs, override value and post-season learning | Continuous improvement |
Table 17. Controlled implementation sequence.
| Rule | Operational meaning |
|---|---|
| Reconcile top-down and bottom-up | Financial targets and detailed choices must agree before approval. |
| Define choice consistently | State whether choice means style, style-color or another customer-visible option. |
| Plan breadth and depth together | Every new choice consumes presentation, size-run and stock investment. |
| Range before allocating | Eligibility, cluster, capacity and lifecycle precede SKU allocation. |
| Phase receipts to demand | Avoid committing stock earlier than lead time and service require. |
| Keep flexibility visible | Separate committed buy, chase reserve, optional capacity and cancellation windows. |
| Protect the exit | Stop replenishment and value terminal stock before the sellable life ends. |
| Measure business outcome | Service, sales, margin, turns, markdown and override value are evaluated together. |
Table 18. High-level operating rules for Merchandise Assortment Planning.
Final design principle The Merchandise Assortment Plan is the retailer's commercial contract between strategy and execution: the right choices, in the right markets, at the right depth and time, within an investment that can achieve the customer, margin and turnover objectives. |
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RETAIL MERCHANDISE MANAGEMENT PAPER
Size curves, constrained assortments, WOS, ABC policy, store index and size-index allocation
Purpose A high-level operating design for allocating the right styles, colors and sizes to each store while respecting lifecycle, local demand and shelf-space constraints. |
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Cybex Retail AI & Analytics Advisory
August 2026 | Illustrative design paper
Apparel inventory should not be managed only at the style or color level. Customer availability is determined at the style-color-size-location level, where a style can appear healthy in total while its highest-demand sizes are already out of stock.
Core principle Store index controls how much inventory a store should receive. Size index controls the shape of that inventory across XXS-XXL. Color class, lifecycle and capacity determine which portions of the curve are carried. |
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The recommended operating model separates four decisions:
Assortment width: which styles, colors and sizes the store should carry.
Depth: how many units are required for each selected color-size combination.
Lifecycle: whether the style is launch, active, winddown or exit.
Network fulfilment: which excluded or out-of-stock sizes remain available through another store, a hub or ecommerce.
All charts and samples in this paper are illustrative. Production parameters should be learned and governed using actual sales, inventory, returns, on-order, promotions, lead times, store capacity, climate, fit and ecommerce data.
A normal size curve is the expected percentage of demand by size for an active style, category or fit family. The curve commonly forms a single peak around the core sizes, but it is not a universal population curve. It varies by customer, fit, brand, garment type, gender category, region, season and channel.
Figure 1. Illustrative chain curve: XXS 4%, XS 10%, S 19%, M 28%, L 22%, XL 12%, XXL 5%.
A curve is most useful when it is stable enough to guide decisions but recent enough to reflect changing demand. Use a hierarchical fallback: store-style history where credible, then store-cluster/category, then chain-category or brand-fit history.
Use net demand, including valid returns treatment, and separate promotional or clearance periods where they distort the normal pattern.
Require minimum observations before using a store-specific curve; shrink noisy curves toward the cluster or chain curve.
Separate true stockout periods from zero demand. A size cannot sell when it was unavailable.
Review fit changes and vendor size relabelling before comparing seasons.
A full run carries every approved size. A shortened run deliberately limits size breadth because the product is winding down, the store has limited presentation space, or local demand does not justify every tail size. The rule should be based on demand coverage and network availability, not a fixed assumption that every small store needs the same sizes.
| XXS | XS | S | M | L | XL | XXL | |
|---|---|---|---|---|---|---|---|
| Full run | carried | carried | carried | carried | carried | carried | carried |
| Limited shelf | – | carried | carried | carried | carried | carried | – |
| Early winddown | – | – | carried | carried | carried | – | – |
| Late winddown | – | – | – | carried | carried | – | – |
Figure 2. Example run widths. Actual carried sizes should shift according to the store size index.
| Status | Illustrative run | Inventory objective | Replenishment rule |
|---|---|---|---|
| Active / full | XXS-XXL | Protect service and complete size runs | Replenish to target WOS by size |
| Limited shelf | XS-XL default | Cover the greatest local demand with fewer slots | Prioritize A colors and A/B sizes |
| Winddown - early | S-XL example | Reduce depth and stop new exposure | Network transfers only; lower target WOS |
| Winddown - late | S-L example | Consolidate sellable units and exit cleanly | No routine replenishment; exception only |
Table 1. Illustrative lifecycle and space policies; category-specific governance is required.
Winddown is a reduction in future commitment, not an instruction to strand random units. Reduce target WOS, stop or restrict purchase orders, transfer fragmented tail inventory toward stores or channels where it can still sell, and preserve the sizes needed to complete the most productive remaining runs.
For a space-constrained store, select the minimum set of sizes that covers a chosen percentage of normalized local demand. A default XS-XL run may be appropriate for one store, while another store may shift to S-XXL. Excluded sizes should remain discoverable and fulfilable through ecommerce or the store network whenever possible.
Weeks of supply (WOS) must be calculated for every size, not only for the total style. Total style WOS can look balanced while core sizes are near stockout and tail sizes are overstocked.
Formula WOS(size) = available inventory(size) / expected weekly unit demand(size). Available inventory should follow a governed definition, such as on hand plus eligible inbound minus reservations or committed demand. |
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Figure 3. Overall style WOS is 3.9 weeks, but M is at 3.0 while XXL is at 7.0.
| Metric | XXS | XS | S | M | L | XL | XXL |
|---|---|---|---|---|---|---|---|
| Weekly demand | 2 | 5 | 10 | 14 | 11 | 6 | 2 |
| Available stock | 8 | 20 | 35 | 42 | 44 | 30 | 14 |
| WOS | 4.0 | 4.0 | 3.5 | 3.0 | 4.0 | 5.0 | 7.0 |
Table 2. Sample WOS calculation across the entire size curve.
Low WOS in an A size is a lost-sales risk and should rank ahead of excess tail inventory.
High WOS in a C size may require a transfer, reduced replenishment, digital fulfilment or markdown action.
When demand is very low, WOS becomes unstable. Apply minimum-demand rules and also track units, age and last-sale date.
Use separate WOS targets by lifecycle, class, vendor lead time and service objective.
ABC classification converts limited capacity into an explicit priority order. A style, color and size can each have a class. The final color-size priority should reflect all three rather than using style rank alone.
| Level | A | B | C | Suggested use |
|---|---|---|---|---|
| Style | Highest productivity | Middle productivity | Tail / test / exit | Controls store penetration and total depth |
| Color | Largest cumulative color demand | Secondary demand | Long-tail fashion color | Controls color count and curve width |
| Size | Core local demand | Secondary local demand | Tail local demand | Controls size inclusion and depth |
Table 3. ABC may use the retailer's preferred 85/10/5 convention or a category-specific alternative.
For a style with color sales mix of Black 48%, Navy 32%, Stone 12% and Sage 8%, Black and Navy form the A-color group, Stone is B and Sage is C. A limited-space store should normally protect Black and Navy before adding Stone; Sage may be limited to selected stores or ecommerce.
| XXS | XS | S | M | L | XL | XXL | |
|---|---|---|---|---|---|---|---|
| Black - A | 1 | 1 | 2 | 3 | 2 | 1 | 1 |
| Navy - A | 0 | 1 | 1 | 3 | 2 | 1 | 0 |
| Stone - B | 0 | 0 | 1 | 1 | 1 | 0 | 0 |
| Sage - C | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
Cell value = opening or target units; excluded colors remain available through the network when possible.
Figure 4. Sample capacity-constrained allocation: two A colors, one B color and no C-color presentation.
| Color / size | A size | B size | C size |
|---|---|---|---|
| A color | First priority; maintain depth | Carry where demand supports | Carry tail only if local index supports |
| B color | Carry core sizes | Selective | Usually network / ecommerce |
| C color | Top stores or test only | Rare | Do not allocate routinely |
Table 4. Illustrative color-size service hierarchy for a capacity-constrained store.
Store index and size index solve different problems and should not be combined into one unexplained factor.
Store index = total depth A store index measures the store's demand intensity relative to comparable stores for a department, class, category or style group. An index of 1.30 suggests approximately 30% more total demand than the comparison-store baseline; 0.70 suggests approximately 30% less. |
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Size index = curve shape A size index measures the store's size mix relative to the chain or cluster size mix. An XL index of 1.25 means XL has 25% greater share at that store than in the baseline curve. It does not by itself mean the store needs 25% more total inventory. |
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Store index(store, class) = store weekly class demand / average weekly class demand for comparable stores.
Size index(store, size, class) = store size-mix percentage / chain-or-cluster size-mix percentage.
Adjusted size weight(size) = baseline curve(size) x size index(store, size).
Normalized store curve(size) = adjusted size weight(size) / sum of adjusted weights for all eligible sizes.
Figure 5. The size index reshapes the curve while normalization keeps the selected curve equal to 100%.
| Store | Store index | Size pattern | Allocation effect |
|---|---|---|---|
| 101 - high volume | 1.35 | Near chain curve | More total units; full curve on A colors |
| 205 - compact | 0.72 | Smaller-size skew | Fewer units; prioritize XXS-L where justified |
| 318 - regional | 0.95 | Larger-size skew | Moderate depth; shift curve toward L-XXL |
Table 5. Store index changes quantity; size index changes the distribution of that quantity.
Every recommendation should retain its inputs, rule version, reason code and approval outcome.
Figure 6. Recommended decision loop for initial allocation, replenishment and redistribution.
1. Forecast store-style-color demand using the average-store forecast, store index, local style affinity, normalized color mix, seasonality, promotion and channel effects.
2. Split store-style-color demand into sizes using the normalized store size curve.
3. Convert forecast to target stock using the target WOS appropriate to class, lifecycle, lead time and service objective.
4. Calculate net need after subtracting usable on-hand and inbound supply and adding reservations or committed demand where applicable.
Illustrative net-need formula Net need = MAX(0, target WOS x weekly SKU forecast - usable on hand - eligible inbound + committed demand). The final quantity is then constrained by pack sizes, presentation minimums, capacity, lifecycle and available network supply. |
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Establish style and color assortment eligibility before assigning depth.
Protect A-style / A-color / A-size combinations first in limited capacity.
Rank needs using expected lost margin, stockout probability, service importance and confidence.
Prevent allocations that create stranded tail sizes or break stronger runs elsewhere.
Use a minimum presentation rule only while the style remains active; reduce or remove it in winddown.
Return reason codes such as CORE_SIZE_STOCKOUT, COLOR_C_CAPACITY_BLOCK or WINDDOWN_TRANSFER_ONLY.
Assume an A-class active style, 22 available presentation units, four eligible colors and the chain curve shown earlier. The store index determines overall demand; store size indices reshape the curve; color ABC and shelf capacity then establish the priority order.
| Step | Input | Black A | Navy A | Stone B | Sage C | Decision |
|---|---|---|---|---|---|---|
| 1 | Color mix | 48% | 32% | 12% | 8% | Classify A/A/B/C |
| 2 | Size eligibility | Full | Core + tails by index | Core only | Network only | Choose curve width |
| 3 | Capacity request | 11 | 8 | 3 | 0 | 22 units total |
| 4 | Lifecycle | Active | Active | Active | Active | Normal WOS for eligible SKUs |
| 5 | Execution | Allocate | Allocate | Allocate selectively | Do not present | Retain ecommerce availability |
Table 6. Example decision sequence for the 22-unit color-size matrix.
A merchant should be able to select any recommended unit and see why it was allocated: forecast, store index, size index, color class, WOS gap, capacity effect, alternative source and expected result. Explainability turns the model into a controlled retail workflow rather than a black-box optimization.
| SKU | From | From WOS | To | To WOS | Reason |
|---|---|---|---|---|---|
| Black / M | Store 101 | 1.6 | Store 205 | 8.1 | A size; high lost-sales risk |
| Navy / XL | Store 318 | 1.9 | Store 101 | 6.4 | Local larger-size index |
| Stone / S | Ecommerce hub | 2.2 | Store 318 | 9.0 | B color; consolidate winddown demand |
Table 7. Illustrative transfer recommendations; apply transfer cost, handling and sell-through thresholds.
The most effective size and color system combines statistical demand with explicit retail policy. Merchants should control thresholds and exceptions, while the system applies them consistently and records results.
| Parameter | Examples | Owner |
|---|---|---|
| Curve hierarchy | Store-style, cluster-category, chain-category | Merchandise planning |
| ABC thresholds | 85/10/5 or category-specific bands | Merchandising + finance |
| Target WOS | By class, lifecycle, lead time and season | Planning + purchasing |
| Capacity | Style/color/size slots or total units | Store operations |
| Lifecycle rules | Launch, active, winddown, exit | Merchandising |
| Transfer economics | Minimum benefit, cost, distance, days remaining | Operations + finance |
| Approval rights | Auto-approve, merchant review, executive exception | Governance owner |
Table 8. Parameter ownership prevents hidden model changes and conflicting rules.
Phase 1 - Visibility: publish curves, WOS, stockouts, broken runs and color-size exceptions.
Phase 2 - Recommendations: propose allocations, replenishment and transfers with reason codes.
Phase 3 - Simulation: allow merchants to change WOS, size breadth, colors, store capacity and lifecycle rules before approval.
Phase 4 - Closed loop: write approved actions back to allocation, transfer or replenishment workflows and measure outcomes.
| Service | Inventory | Decision process |
|---|---|---|
| Core-size in-stock rate | WOS by size and color | Recommendation acceptance |
| Complete size-run rate | Aged units and inventory turns | Merchant time saved |
| Stockout duration | Full-price sell-through | Override reason and outcome |
| Lost-sales estimate | GMROI and markdown exposure | Forecast and index accuracy |
Table 9. Balanced scorecard for service, inventory productivity and adoption.
Final design principle Allocate the fewest units that can deliver the required service level, in the colors and sizes the local customer is most likely to buy, while preserving network access to the broader assortment. |
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| Rule | Operational meaning |
|---|---|
| Normal curve | Maintain all eligible sizes; depth follows size-level WOS. |
| Limited shelf | Carry the smallest set of sizes and colors that reaches the local demand-coverage target. |
| Winddown | Lower target WOS, stop new exposure, and consolidate sellable units. |
| A colors | Protect first; usually receive the broadest size run. |
| B colors | Core sizes and selective stores. |
| C colors | Test, top-store or ecommerce/network availability. |
| Store index | Scales total store demand and inventory depth. |
| Size index | Reshapes the store curve, then is normalized. |
| WOS | Calculate at style-color-size-location; do not rely only on style totals. |
| Human control | High-impact actions require transparent reasons and approval. |
Table 10. High-level policy summary.
APPAREL MERCHANDISE MANAGEMENT PAPER
Data warehouse, normalized demand, seasonality, lead time, safety stock, in-stock service and forward-week inventory
Purpose A high-level forecasting design that converts governed retail data into demand, stock and receipt projections used consistently by Merchandise Assortment Planning, Merchandise Purchasing and DC Allocation. |
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Cybex Retail AI & Analytics Advisory
August 2026 | Illustrative design paper
An apparel stock forecast is more than a sales projection. It is a forward-week view of demand, receipts, inventory position, safety stock, availability and exit risk at the level required to make merchandise decisions. The forecast should be built once on governed data and then consumed consistently by assortment planning, purchasing and DC allocation.
Core principle Forecast unconstrained customer demand first. Then convert demand into a stock requirement using lead time, review cycle, target in-stock service, safety stock, WOS limits, presentation rules, packs, capacity and lifecycle. |
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Demand forecast: expected unconstrained unit demand by forward retail week.
Stock forecast: projected beginning stock, receipts, demand, transfers, markdowns and ending stock.
Decision requirement: the units, timing and location needed to achieve the governed service and inventory objective.
| Consumer | Forecast decision | Required level |
|---|---|---|
| Merchandise Assortment Plan | Breadth, depth, lifecycle, color and size investment | Department -> class -> style / choice |
| Merchandise Purchasing | Buy quantity, receipt timing, open-to-buy and supplier commitments | Style-color-size by receipt week |
| DC Allocation | Destination, quantity, release timing and replenishment priority | SKU-store by ship / arrival week |
Table 1. One forecast foundation, expressed at the grain required by each decision.
All numerical examples and policy values in this paper are illustrative. Production parameters should be calibrated through backtesting, service economics and merchant governance.
Figure 1. A governed data warehouse creates a single forecast foundation for the assortment plan, purchasing and DC allocation.
Use a common retail calendar, product hierarchy, location hierarchy and currency / unit basis.
Retain raw observations, normalized observations, overrides, parameters and selected forecast versions.
Separate demand forecasting from supply feasibility so constrained sales do not define future demand.
Publish weekly forecasts at reconciled levels: class, style, color, size, DC, store cluster and store.
Attach reason codes, confidence and model version to every merchant-facing recommendation.
The data warehouse should preserve atomic retail events and publish conformed weekly facts. The forecast engine can then rebuild any history, explain adjustments and reconcile plans without relying on spreadsheets as the system of record.
| Domain | Minimum facts | Forecast use |
|---|---|---|
| Sales / returns | Transaction date, SKU, store, units, value, discount, return | Demand history, price response, returns normalization |
| Inventory | Daily / weekly on hand, available, reserved, in transit, on order | In-stock censoring, stock position, WOS and receipt need |
| Purchasing | PO line, supplier, order date, due date, receipt date, cancellations | Actual lead time, reliability and future receipts |
| Product | Style, color, size, season, class, cost, ticket, lifecycle | Hierarchy, analogs, margin and eligibility |
| Location | Store / DC, cluster, capacity, climate, opening / closure | Store indexing, ranging and allocation |
| Calendar / events | Retail week, holidays, campaigns, weather / local events if governed | Seasonal alignment and causal adjustments |
Table 2. Core warehouse domains for an apparel stock forecast.
Gold forecast fact One record per forecast version x retail week x SKU x location or location cluster, with demand, normalized demand, seasonal index, baseline, selected forecast, confidence, in-stock target, safety stock, projected inventory and recommendation. |
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Complete product and location keys
No negative usable inventory without an explained adjustment
PO dates and quantities reconcile to receipts
Ranged / not-ranged status is explicit
Promotions and markdown periods are identifiable
History snapshots are immutable and versioned
Figure 2. Illustrative history: normalization removes known distortions; de-seasonalization reveals the underlying baseline.
| Step | Treatment | Control |
|---|---|---|
| 1. Validate | Remove duplicate / corrupt events; reconcile returns and transfers | Never silently delete demand |
| 2. Availability | Flag stockout, broken size run and low in-stock periods | Do not interpret zero sales as zero demand |
| 3. Event effects | Identify promotion, markdown, store closure, bulk sale and launch | Retain event factor and original sales |
| 4. Impute demand | Estimate lost demand only where evidence supports censoring | Cap and confidence-score the correction |
| 5. Normalize | Restate to a comparable price, store-week and lifecycle basis | Preserve both raw and normalized history |
| 6. De-seasonalize | Divide normalized demand by the governed seasonal index | Rebase indices to average 1.00 |
Table 3. An auditable preparation sequence for sales history.
Key warning Sales are observed demand only when the item was available, ranged and discoverable. Apparel styles with missing core sizes may be demand-constrained even when total style stock is positive. |
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Seasonality describes the repeatable timing pattern around the baseline. It may be estimated at department, class, attribute, climate cluster or style-family level depending on history depth. A new fashion style normally inherits an analog or pooled seasonal profile until its own evidence is credible.
| Component | Definition | Apparel treatment |
|---|---|---|
| Baseline | Underlying level after normalization and de-seasonalization | Trend-cap to avoid runaway extrapolation |
| Seasonal index | Relative demand by retail week; average normally equals 1.00 | Use class / climate / attribute hierarchy |
| Lifecycle curve | Launch, build, peak, decay and exit shape | Override annual seasonality for short-life fashion |
| Event factor | Incremental effect of holiday, campaign, promotion or weather | Keep separate from baseline when possible |
| Re-seasonalized forecast | Baseline x seasonal index x approved event factor | Reconcile to plan totals and lifecycle units |
Table 4. Demand components should remain visible rather than being buried in one number.
De-seasonalized baseline = normalized demand / seasonal index.
Re-seasonalized forecast = projected baseline x seasonal index x approved event factor.
For a short-life style, use a lifecycle curve whose weekly proportions sum to 100% of the style demand plan, then distribute by color, size and location indices.
Hierarchy rule Estimate seasonality at the lowest level with stable evidence, but fall back to a pooled parent or attribute group when observations are sparse. Reconcile child forecasts to the approved parent total. |
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Figure 3. The forecast horizon must extend beyond the protection period and the decision lead time.
| Term | Meaning | Forecast implication |
|---|---|---|
| Supplier lead time | Order release to supplier-ready or ship date | Determines the last week a purchase can change supply |
| Logistics lead time | Ship through receiving and put-away | Include actual distribution delay, not only vendor promise |
| Review period | Time until the next replenishment / buying decision | Adds exposure between decisions |
| Protection period | Lead time + review period | Forecast and uncertainty window covered by reorder point |
| Forward weeks | Future retail weeks retained in the forecast version | 13, 26 or 52 weeks depending on decision horizon |
Table 5. Time parameters connect the forecast to executable decisions.
Use realized lead-time distributions by supplier and route, not only contracted averages.
Freeze or taper forecasts beyond the exit week; safety stock must not create stock after the sellable life.
Align order cut-offs, DC release dates and store arrival weeks to the retail calendar.
Retain forward forecasts even where supply is unavailable so lost opportunity remains visible.
Figure 4. Illustrative relationship: the final points of in-stock service require increasing inventory protection.
For weekly independent forecast errors and stable lead time, an operational approximation is: Safety stock = z x weekly forecast-error standard deviation x square root of protection weeks. When lead time also varies, combine demand and lead-time variance or simulate the distribution. Backtest against realized service and excess.
| Policy segment | Illustrative cycle service | z factor | Apparel note |
|---|---|---|---|
| A product / A store | 98.0% | 2.05 | Protect core and proven fashion |
| A / B or B / A | 97.0% | 1.88 | High service with capacity control |
| B / B | 95.0% | 1.65 | Balanced default |
| C / C | 90.0% | 1.28 | Limited depth or network fulfilment |
| Winddown | Economic / exit rule | N/A | Do not replenish solely to restore a size run |
Table 6. Illustrative service policy; calibrate by margin, substitution, lifecycle and space.
Measure availability only while an item is ranged and sellable. Report SKU in-stock, complete color-size run, demand-weighted in-stock and stockout duration. A style can appear in stock while the highest-demand size or color is unavailable.
Figure 5. Different methods may be appropriate by lifecycle and data sufficiency; merchants can compare the alternatives before selection.
| Alternative | Best fit | Key parameters |
|---|---|---|
| Moving average / EWMA | Stable replenishment with adequate own history | History window, decay, outlier handling |
| Trend + seasonal | Carryover / basic apparel | Trend window, cap / floor, seasonal hierarchy |
| Lifecycle curve | Short-life fashion and launch | Total demand, launch week, peak, decay, exit |
| Analog / attribute | New style with limited history | Analog set, similarity weights, price and store factors |
| Merchant plan | Strategic buy, event or new concept | Plan version, override horizon, owner and reason |
| Hybrid ensemble | Mixed evidence and operational scale | Method weights, error window, confidence threshold |
Table 7. Forecast alternatives should be parameter-controlled and backtested.
Separation of concerns The selected demand forecast estimates what customers would buy. The stock forecast applies receipts, safety stock, WOS, packs, capacity, lifecycle and available supply to show what inventory is required and feasible. |
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A parameter-driven design permits different forecasting behaviour without rebuilding the application. Parameters should be effective-dated, versioned, inherited through hierarchy and overrideable only by authorized roles.
| Parameter family | Examples | Decision effect |
|---|---|---|
| History | Weeks used, stockout correction, return treatment, promo normalization | Defines the comparable demand signal |
| Method | Moving average, EWMA, trend-seasonal, lifecycle, analog, ensemble | Creates alternative demand paths |
| Hierarchy | Class, attribute, climate cluster, style, color, size, store | Controls pooling, inheritance and reconciliation |
| Time | Forward weeks, lead time, review cycle, freeze window, exit week | Defines executable horizon |
| Service / stock | In-stock target, z factor, min / target / max WOS, presentation | Converts demand into stock requirement |
| Execution | Pack, MOQ, capacity, DC availability, transfer eligibility | Converts requirement into a feasible action |
| Governance | Override limits, owner, reason code, expiry, approval | Controls human judgment and auditability |
Table 8. A practical parameter dictionary for apparel stock forecasting.
Backtest eligible methods on rolling historical cut-offs using the same data that would have been available then.
Select by WAPE, bias, service outcome and stability - not error alone.
Use a confidence score to determine whether style-level history or a pooled analog should dominate.
Reconcile style-color-size-store forecasts to approved class and channel plans without erasing local demand shape.
Store the unadjusted model result, merchant override and final consensus forecast separately.
Closed-loop learning: realized sales, stock and service feed back into the next forecast.
Figure 6. The forecast must reconcile across downstream decisions and learn from actual sales, stock and service.
The Merchandise Assortment Plan converts demand opportunity into planned breadth, depth, timing and option productivity. It should receive a baseline demand forecast plus scenario parameters, not only a single seasonal total.
| MAP decision | Forecast input | Planning output |
|---|---|---|
| Class / subclass opportunity | Forward demand, trend, seasonality, margin and service | Sales, receipt, stock and markdown targets |
| Choice count / breadth | Demand concentration and forecast confidence | Number of styles and colors by store cluster |
| Depth | Weekly demand, size curve, color share and lead time | Initial and replenishment units per choice |
| Lifecycle timing | Launch, peak, decay and exit forecast | Floor dates, receipt windows and exit dates |
| Scenario | Base, upside, downside and event alternatives | Investment and open-to-buy options |
Table 9. The forecast supports both financial and assortment structure decisions.
MAP rule Assortment breadth consumes presentation and safety-stock investment. Add choices only when incremental demand and margin exceed the service, space and fragmentation cost of carrying another style-color-size run. |
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Purchasing converts the forecast into time-phased receipts and supplier commitments. It must consider inventory position, forecast through the protection period, safety stock, planned markdowns, existing open orders, MOQ, packs, lead time and the remaining sellable weeks.
| Line | Illustrative calculation | Units |
|---|---|---|
| Forecast demand: weeks 1-10 | Weekly re-seasonalized forecast summed | 820 |
| Safety stock at first receipt | 97% service; forecast-error model | 72 |
| Presentation / launch minimum | Required color-size display depth | 48 |
| Gross stock requirement | MAX(demand + safety stock, presentation) | 892 |
| Less usable on hand | Available and eligible for sale | -210 |
| Less eligible on order | Confirmed to arrive inside need window | -300 |
| Net purchase need | Before pack, MOQ and budget | 382 |
| Executable order | Rounded to 12-unit pack | 384 |
Table 10. Illustrative purchase-need calculation. Avoid double-counting presentation stock if it is already embedded in the target.
Base buy: selected forecast and normal service policy.
Upside reservation: optional or delayed commitment for high-uncertainty demand.
Chase buy: shorter lead-time replenishment after early sales evidence.
Exit protection: cap receipts so inventory can sell through by the governed exit date.
Open-to-buy connection The forecast should translate unit need into retail value, cost and margin by receipt week. Purchasing approves only the feasible portion within supplier, cash, capacity and open-to-buy constraints. |
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| XXS | XS | S | M | L | XL | XXL | |
|---|---|---|---|---|---|---|---|
| A store | 0 | 2 | 5 | 7 | 5 | 2 | 0 |
| B store | 1 | 4 | 9 | 12 | 9 | 4 | 1 |
| C store | 0 | 3 | 7 | 10 | 8 | 3 | 0 |
| Digital / hub | 0 | 1 | 3 | 5 | 4 | 2 | 0 |
Figure 7. DC allocation need reflects forecast demand, current inventory, safety stock, store index and size index.
DC allocation distributes constrained supply to the SKU-location combinations where it protects the most expected demand and margin. The process should calculate need first, then optimize against available DC stock, packs, store capacity and shipment rules.
| Factor | Application in allocation |
|---|---|
| Store index | Scales chain or cluster demand to the location based on normalized productivity and eligibility. |
| Size index | Distributes style or color demand across sizes based on local / cluster demand shape. |
| Color share | Limits breadth and depth to proven or strategic colors. |
| In-stock target | Sets differential protection by product ABC, store ABC and lifecycle. |
| Inventory position | Subtracts usable on hand and eligible inbound before ranking need. |
| Forward weeks | Uses demand through arrival and review, not only last-week sales. |
Table 11. Forecast elements used in initial and replenishment allocation.
Illustrative need: SKU-store forecast = style forecast x store index x color share x size index. Net allocation need = target stock through the protection period + safety stock - inventory position, then constrained and pack-rounded.
Assume a carryover knit style with enough history for a trend-seasonal forecast. The selected 10-week unconstrained demand is 820 units. The first effective receipt arrives after a six-week lead time and one-week review period. Forecast error over the seven-week protection period supports 72 units of safety stock at the selected service target.
| Decision stage | Forecast transformation | Illustrative result |
|---|---|---|
| Demand preparation | Raw sales corrected for stockouts and promotion; de-seasonalized | Weekly baseline |
| Forecast selection | Trend-seasonal beats eligible alternatives in backtest | 820 units / 10 weeks |
| MAP | Forecast distributed to 4 colors and 7 sizes; breadth constrained by store tier | Approved option plan |
| Purchasing | Demand + safety stock - inventory position; pack-rounded | 384-unit order |
| DC allocation | Store index x color share x size index; subtract local stock | SKU-store need matrix |
| Reforecast | Early sales update baseline and confidence; receipt / exit dates retained | Chase, hold or cancel decision |
Table 12. One forecast version, transformed for three downstream decisions.
Color shares sum to 100% of the style forecast before rounding.
Size indices sum to 100% within each style-color and destination segment.
Store indices reconcile store demand to the approved channel / cluster total.
Allocated units cannot exceed available-to-allocate DC inventory.
Beginning stock + receipts + transfers in - demand - transfers out - adjustments = ending stock.
Projected ending stock after the exit week is treated as markdown / transfer exposure.
Figure 8. Backtesting should compare accuracy and bias by horizon, lifecycle, class and forecastability segment.
| Measure | Purpose | Recommended cut |
|---|---|---|
| WAPE / MAE | Forecast magnitude of error | 1, 4, 8, 13 and lead-time horizons |
| Bias | Systematic over- or under-forecast | Method, merchant, class and lifecycle |
| In-stock / fill rate | Customer service delivered | Product ABC x store ABC x size |
| Turns / average WOS | Inventory productivity | Class, lifecycle, channel and location |
| Markdown / terminal stock | Exit quality | Season, style and color |
| Override value add | Whether human changes improve the outcome | Reason code and approver |
| Forecast stability | Change between forecast versions | Freeze window and horizon |
Table 13. Forecast accuracy is necessary, but operational and financial outcomes complete the scorecard.
Every parameter and forecast version has an owner, effective date and approval status.
Overrides record original value, new value, reason, owner, expiry and expected outcome.
Methods are promoted only after rolling-origin backtests and controlled pilot results.
Actual service and excess recalibrate safety-stock and in-stock policies.
| Phase | Capability | Merchant outcome |
|---|---|---|
| 1. Foundation | Conformed warehouse, weekly snapshots, in-stock flags and forecast versioning | Trusted sales and stock history |
| 2. Baseline | Normalization, seasonality, lead-time and selected forward-week forecast | Explainable demand baseline |
| 3. Stock forecast | Safety stock, in-stock targets, WOS, receipts and ending inventory | Time-phased stock requirement |
| 4. Decision integration | MAP, purchasing and DC allocation interfaces | One reconciled planning process |
| 5. Closed loop | Backtesting, overrides, alerts, realized benefit and parameter tuning | Continuous improvement |
Table 14. A controlled implementation sequence.
| Rule | Operational meaning |
|---|---|
| Forecast demand, not constrained sales | Correct stockout and broken-size censoring before projecting demand. |
| Keep raw and adjusted history | Every normalization and override remains auditable. |
| De-seasonalize before trend | Estimate the baseline separately, then apply seasonality and events. |
| Forecast far enough forward | Horizon must exceed lead time, review period and decision window. |
| Differentiate service | Target in-stock and safety stock vary by value, store and lifecycle. |
| Separate need from feasibility | Calculate unconstrained requirement before supply, pack, capacity and budget limits. |
| Reconcile every level | Style, color, size and store forecasts tie to the approved merchandise plan. |
| Measure business outcome | Accuracy, bias, service, turns and markdowns are evaluated together. |
Table 15. High-level operating rules for Apparel Stock Forecast.
Final design principle A strong apparel stock forecast creates one trusted forward view of demand and inventory, while preserving the different decisions made by assortment planners, buyers and DC allocators. The system should be parameter-driven, explainable and continuously recalibrated. |
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RETAIL MERCHANDISE MANAGEMENT PAPER
Safety stock, service levels, WOS policy, ABC priorities, investment efficiency and inventory turns
Purpose A high-level operating design for maximizing in-stock service with the least practical inventory investment while improving stock turnover and controlling excess. |
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Cybex Retail AI & Analytics Advisory
August 2026 | Illustrative design paper
Stock optimization is not the pursuit of the highest possible inventory level. It is the disciplined selection of the lowest practical inventory position that can deliver the required customer service, presentation, replenishment and financial outcomes for each SKU-location.
Core principle Optimum stock balances the expected cost of stockouts against the cost of holding, transferring and marking down inventory. Product importance, store importance, lifecycle, lead time and demand variability determine where investment should be protected. |
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The operating model separates six decisions:
Service objective: the in-stock or fill-rate target appropriate to the product and store.
Safety protection: the buffer required for demand and lead-time uncertainty.
Operating band: minimum, target and maximum WOS for each policy segment.
Investment priority: which product-store combinations receive scarce units first.
Network action: replenish, transfer, retain, consolidate, markdown or exit.
Closed-loop learning: compare service, turns, forecast error and inventory cost after each action.
All charts, service levels, WOS bands and examples are illustrative. Production policies should be calibrated from actual demand, lost-sales estimates, margins, lead times, review cycles, pack sizes, capacity, lifecycle, forecast error and transfer economics.
Optimum stock is the policy-driven inventory position at which the next unit of stock is no longer expected to create enough service or margin benefit to justify its holding, transfer, space and markdown risk. It is a range, not a permanently fixed number, because forecasts, lead times and lifecycle conditions change.
Working definition Optimum stock = the smallest feasible inventory position that meets the selected service target and presentation requirement, within maximum WOS, capacity, lifecycle and investment constraints. |
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Figure 1. Service gains diminish as investment rises; the economic optimum occurs before the theoretical maximum in-stock rate.
Understocking produces avoidable stockouts, lost margin and incomplete assortments.
Overstocking can add very little service while reducing turns and increasing markdown exposure.
The optimum varies by product ABC, store ABC, lifecycle, lead time, substitutability and margin.
The objective is not one chain-wide WOS number; it is a governed SKU-location policy.
An in-stock target expresses the probability or percentage of customer demand the retailer intends to satisfy from available inventory. Cycle service level and unit fill rate are related but different measures; the policy should name which one it governs. A higher service target requires disproportionately more safety stock as the target approaches 100%.
Safety stock formula - demand uncertainty When lead time is stable: Safety stock = z x standard deviation of demand during the protection period. When both demand and lead time vary, use a combined variance model and validate the result against observed stockout behaviour. |
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| Illustrative cycle service | z factor | Typical policy use |
|---|---|---|
| 90% | 1.28 | Long-tail or highly substitutable demand |
| 95% | 1.65 | Balanced service segment |
| 97.5% | 1.96 | Important product-store combinations |
| 99% | 2.33 | Exceptional high-service combinations |
Table 1. Standard normal service factors; use only when the statistical assumptions are appropriate.
Protection period normally includes supplier or transfer lead time plus the replenishment review period. Forecast demand over that period establishes the base requirement; safety stock protects the uncertainty around it. Presentation minimums and pack constraints may raise the executable quantity.
Figure 2. A min-target-max policy triggers replenishment before the safety floor and prevents routine buying above the maximum.
Inventory position = usable on hand + eligible on order + confirmed inbound - reservations - backorders.
Reorder point = forecast demand during the protection period + safety stock.
Net need = MAX(0, target inventory position - current inventory position), then adjusted for packs, minimum presentation, capacity and lifecycle.
WOS turns the stock policy into an understandable operating band. Minimum WOS is the replenishment trigger or starvation threshold. Target WOS is the desired post-action position. Maximum WOS limits excess investment and identifies transfer or markdown candidates. Each threshold should vary by product class, store class, lifecycle and lead time.
Figure 3. Illustrative active-product WOS bands; long-lead categories may require materially higher coverage.
| Product class | Minimum WOS | Target WOS | Maximum WOS | Primary response |
|---|---|---|---|---|
| A | 3 | 5 | 8 | Protect service; replenish first |
| B | 2 | 4 | 7 | Balance service and investment |
| C | 1 | 3 | 5 | Limit depth; use network availability |
Table 2. Illustrative active-lifecycle WOS policy. Launch and winddown require separate bands.
Product ABC and store ABC solve different allocation questions. Product ABC ranks the economic or service importance of the item. Store ABC ranks the demand productivity, strategic role and capacity of the location. The two classifications form a service and investment matrix.
A practical product ranking may use cumulative annualized gross margin, net sales or demand contribution. Cybex can support the retailer's 85/10/5 convention: A items produce the first 85% of the selected contribution, B the next 10% and C the final 5%. Lifecycle and strategic items may require governed overrides.
Store classification should consider sales volume, category productivity, local demand confidence, strategic presentation role, fulfilment capability and space. A high-volume A store is not automatically entitled to every C product; capacity and local relevance still apply.
| A store | B store | C store | |
|---|---|---|---|
| A product | 98.5% | 97.5% | 96.5% |
| B product | 97.0% | 96.0% | 94.5% |
| C product | 95.0% | 93.0% | 90.0% |
Figure 4. Product-store service matrix: highest protection is reserved for combinations with the greatest service and financial value.
| Combination | Service posture | Stock posture | Network posture |
|---|---|---|---|
| A product / A store | Highest governed target | Fullest justified depth | Local availability protected |
| A product / C store | High but capacity-aware | Core depth only | Rapid transfer or hub backup |
| C product / A store | Selective or test | Presentation minimum | Replenish only on evidence |
| C product / C store | Lowest routine target | Normally excluded | Ecommerce / network access |
Table 3. Illustrative product-store policy combinations.
The optimization objective should maximize expected full-price demand served and margin protected, subject to an inventory budget, store capacity, availability, pack sizes and lifecycle. It should not maximize service independently of cost, because the last fractions of service can require disproportionate inventory.
Figure 5. Optimum stock occurs near the minimum of expected shortage cost plus holding and markdown cost.
Optimization objective Maximize expected served margin and service, less holding, transfer and markdown cost, subject to inventory investment, capacity, pack, lifecycle and network constraints. |
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A practical ranked need can combine forecast demand, service gap, expected lost margin, product ABC, store ABC, forecast confidence, lifecycle and alternative availability. Every recommendation should retain a reason code and the assumptions that produced it.
Figure 6. Closed-loop optimization for initial allocation, replenishment, transfer and exit decisions.
Forecast SKU-location demand and demand variability over the protection period.
Apply product ABC, store ABC, lifecycle and strategic eligibility.
Set the service target and calculate safety stock.
Calculate minimum, target and maximum WOS and the resulting net need.
Apply presentation, pack, capacity, open-order and available-supply constraints.
Rank replenishment, transfer, retain, markdown and exit actions by expected economic benefit.
Require approval for governed exceptions and write accepted actions to execution workflows.
Measure in-stock, turns, forecast error, markdowns and realized outcome; recalibrate.
The Store Stock Planner provides a practical merchant interface for the policy. The WOS slider defines starvation, healthy and surplus bands; capacity identifies required exits; the style grid ranks service gaps; and color-size detail prevents a healthy style total from hiding broken selling combinations.
Figure 7. Cybex Store Stock Planner example supplied by the user; values shown are application data, not policy recommendations in this paper.
| Planner element | Optimization role | Recommended enhancement |
|---|---|---|
| WOS policy slider | Defines minimum and maximum operating band | Allow bands by product ABC, store ABC and lifecycle |
| Styles on floor / capacity | Measures assortment pressure | Separate style slots, SKU slots and unit capacity |
| Starved styles | Identifies service risk | Rank by lost margin, ABC and forecast confidence |
| Transfer candidates | Releases excess investment | Include receiving-store benefit and transfer cost |
| Markdown candidates | Flags persistent surplus | Use age, lifecycle and projected sell-through |
| Color / size tiles | Exposes broken availability | Show safety floor, target and reason code by SKU |
Table 4. Connecting the planner interface to the optimum-stock policy.
Assume an A product in an A store. Forecast weekly demand is 20 units, lead time is two weeks, review period is one week, protection-period demand is therefore 60 units, and governed safety stock is 18 units. The presentation minimum is 12 units and current inventory position is 49 units.
| Step | Calculation | Units | Interpretation |
|---|---|---|---|
| 1 | Protection-period forecast: 20 x 3 weeks | 60 | Expected demand before the next effective review |
| 2 | Add governed safety stock | 18 | Protects demand and lead-time uncertainty |
| 3 | Target inventory position | 78 | 60 forecast + 18 safety stock |
| 4 | Current inventory position | 49 | On hand + eligible inbound - commitments |
| 5 | Calculated net need | 29 | 78 target - 49 current |
| 6 | Pack rounding | 30 | Order pack is 6 units |
| 7 | Maximum-WOS test | Pass | Result remains below the 8-WOS ceiling |
Table 5. Illustrative optimum-stock calculation for one SKU-location.
Result Replenish 30 units if supply and capacity are available. The recommendation should be reduced or deferred if a transfer can meet the need faster or if the style is entering winddown. |
|---|
| SKU | From | From WOS | To | To WOS | Action rationale |
|---|---|---|---|---|---|
| A item | Store 101 | 1.6 | Store 205 | 11.2 | Protect A/A service and avoid new buy |
| B item | Store 205 | 1.9 | Store 318 | 8.4 | Improve service within transfer-cost threshold |
| C item | Ecommerce hub | 3.1 | Store 101 | 13.0 | Consolidate tail demand and release space |
Table 6. Illustrative network actions after min-max and ABC evaluation.
The policy should be transparent and merchant-controlled. Parameters must have owners, version history and effective dates. Recommendations should explain the forecast, service target, safety stock, WOS band, ABC classes, capacity effect and alternative source.
| Parameter | Examples | Owner |
|---|---|---|
| Service targets | Product ABC x store ABC x lifecycle | Merchandise planning |
| Safety-stock method | Demand variance, lead-time variance, z factor | Planning / data science |
| WOS policy | Minimum, target and maximum bands | Planning / purchasing |
| Capacity | Style, SKU and unit limits | Store operations |
| Cost model | Lost margin, carrying, transfer, markdown | Finance |
| Exceptions | Launch, strategic, display, exit | Merchandising |
| Approval rights | Auto, merchant review, executive exception | Governance owner |
Table 7. Governed parameters for a controlled optimization process.
| Service | Inventory productivity | Decision quality |
|---|---|---|
| In-stock % by ABC matrix | Inventory turns | Recommendation acceptance |
| Unit fill rate | Average WOS and excess WOS | Realized benefit vs predicted |
| Stockout duration | Markdown and aged-stock exposure | Override reason and outcome |
| Complete color-size availability | GMROI / return on inventory | Forecast and safety-stock accuracy |
Table 8. Measure service and inventory productivity together; improving one while damaging the other is not optimization.
Phase 1 - Visibility: publish min, target and max WOS, service gaps, ABC matrix, excess and broken availability.
Phase 2 - Recommendations: rank replenishment, transfer, markdown and exit actions with reason codes.
Phase 3 - Simulation: allow merchants to adjust service, WOS, capacity, safety factors and investment budget.
Phase 4 - Closed loop: execute approved actions, measure results and recalibrate parameters.
Final design principle Protect the customer promise where it creates the most value, and remove inventory where it adds cost without meaningful service. Optimum stock is the governed point where service, investment and turnover are jointly strongest. |
|---|
| Rule | Operational meaning |
|---|---|
| Optimum stock | Lowest feasible inventory position that meets governed service and presentation requirements. |
| Safety stock | Buffer for uncertainty, not a substitute for poor forecasting or unreliable lead time. |
| Minimum WOS | Replenishment trigger or starvation threshold. |
| Target WOS | Desired post-action coverage. |
| Maximum WOS | Ceiling that prevents excess and prompts transfer or markdown review. |
| Product ABC | Ranks economic and service importance of stock. |
| Store ABC | Ranks local productivity, strategic role and fulfilment value. |
| Service matrix | Sets differentiated targets for product-store combinations. |
| Network first | Transfer usable excess before buying when economics and timing support it. |
| Turns | Annualized cost of sales / average inventory at cost; keep bases consistent. |
| Human control | High-impact actions require transparent reasons and approval. |
Table 9. High-level policy summary.
WOS = available inventory / expected weekly demand.
Reorder point = protection-period forecast + safety stock.
Target inventory position = forecast through protection period + safety stock, adjusted for presentation and policy constraints.
Inventory turns = annualized cost of sales / average inventory at cost. A retail-value turns measure may also be used, but numerator and denominator must use the same valuation basis.