Metrics are important and allow you to understand your store and how it performs better. This glossary explains the terms you may encounter across Tightly.

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A two-way SKU segmentation — ABC by value contribution, XYZ by demand variability — used to apply different planning policies to high-value/steady vs low-value/erratic items. Extends the A/B/C Class concept below.

A finished good that must be built or kitted from component items before it can be sold, tracked via a bill of materials.

Units in stock that are not already allocated or committed to open orders, and are free to be sold.

Demand that has been accepted but not yet fulfilled because the item was out of stock, to be shipped once replenished — as opposed to a lost sale, where the customer walks away.

The process of establishing a forecast starting point for a new or replacement product using the historical sales data of a related predecessor product.

The fixed quantity increment in which a product must be produced or ordered.

The list of component items and quantities required to build one unit of an assembly.

A group of individual SKUs sold together as a single sellable unit, without requiring pre-assembly into a new physical product.

When a new or promoted product captures demand that would otherwise have gone to an existing one, so the incremental gain is smaller than the headline sales suggest.

The fixed number of units contained in a single case or carton as sold by the supplier.

A categorization of SKUs (e.g. A/B/C) based on their contribution to revenue or units sold, used to prioritize planning attention.

The ratio of demand's standard deviation to its mean — a measure of how erratic a SKU's demand is. High-CV items need more safety stock and are harder to forecast.

Forecasting demand for a product with little or no sales history (a new launch), typically by borrowing signal from similar items or a predecessor until real data accumulates.

The individual items that make up a bundle or assembly.

An item carried and replenished year-round rather than tied to a season or drop — the counterpart to seasonal product, and usually the bulk of a catalog.

A signal showing a sustained decline in sales velocity over recent periods, indicating waning demand for a product.

The working portion of inventory expected to sell between replenishment cycles, over and above safety stock — the part that turns over in normal trading.

The number of days current inventory is expected to last given the forecasted sales rate.

Inventory that has recorded little to no sales activity over an extended period and is unlikely to sell through at full price.

The underlying customer want for a product, estimated from sales, traffic, and other behavioral signals — independent of whether inventory was actually available to fulfill it.

The total value of markdowns applied to sales during the period — the difference between full price and the price actually paid.

The average number of days inventory is held before it sells (365 ÷ turns) — the finance-side view of turnover, closely related to Days of Cover.

The order quantity that minimizes the combined cost of ordering and holding inventory — the classic trade-off between ordering too often and carrying too much.

Inventory beyond foreseeable demand (excess) or no longer sellable at full price (obsolete) — the write-down and liquidation risk carried on the balance sheet. The finance-standard umbrella over deadstock and overstock.

The percentage of demand met from stock on hand without a stockout or backorder — a core customer-service metric. Contrast OTIF, which measures a supplier's delivery to you.

The plain-language flip of a forecast error metric, usually expressed as 1 − error (e.g. 100% − WMAPE) so higher is better. The number most often reported to the business.

The average signed error (forecast − actual). Persistent positive bias means chronic over-forecasting (excess stock); negative means under-forecasting (stockouts). Distinct from accuracy, which ignores direction.

How far into the future the forecast projects (e.g. the next 12 weeks). It's normally set to at least cover the lead time plus the review cycle so orders can be planned in time.

The share of units sold at full price before any markdown — a margin-health signal distinct from overall sell-through, which counts discounted units too.

Estimated revenue that would have been earned if a product hadn't been out of stock or otherwise unavailable to sell — a proxy for demand the business failed to capture.

Gross margin dollars earned per dollar of average inventory invested (gross margin ÷ average inventory cost). The headline profitability-of-inventory metric buyers are measured on.

Total sales revenue before deducting discounts, returns, or taxes.

An overall indicator (e.g. Healthy, At Risk, Understocked, Overstocked) summarizing a SKU's inventory position relative to forecasted demand.

Products showing strong underlying demand signals (e.g. high sell-through, low returns, healthy velocity) that are under-promoted or under-stocked relative to their potential.

A relative indicator of how significant a SKU's replenishment recommendation is to overall business performance (e.g. based on revenue or margin contribution).

Units of inventory currently on hand and available.

How many times inventory is sold and replaced over a period, calculated as cost of goods sold ÷ average inventory value. Higher turns mean working capital is recycled faster.

The full cost of getting a unit into the warehouse — unit cost plus freight, duties, insurance, and handling. The correct basis for true unit margin.

The most recent date on which a SKU had zero or negative available inventory.

The number of days between placing an order with a supplier and receiving it into stock.

A more granular, bottom-up plan that translates the Merchandise Financial Plan into actual SKUs — specifying style count, color/size assortment, price points, and unit quantities by category. It's where the financial targets set in the MFP get turned into a concrete product assortment.

Lost Sales multiplied by sell price — the estimated revenue forfeited due to stockouts.

Estimated units of demand that went unmet because a product was out of stock.

The average size of the forecast miss in units, ignoring whether it was over or under. Easy to interpret, but not comparable across SKUs of very different volumes.

Orders to produce assemblies or kits from component stock.

The average absolute percentage gap between forecast and actual demand across items or periods; lower is better. Simple to read, but it overweights errors on low-volume SKUs, so it can mislead on a long tail of slow sellers.

Total markdown dollars as a percentage of sales (or of full-price value) — how much price was given up to clear stock. The rate behind the Discount Amount figure.

A top-down financial plan, typically built by month and by department/category, that sets planned sales, markdowns, receipts, and ending inventory targets against a target margin and turn. It's the financial "guardrail" that line plans and buys must roll up into.

The smallest quantity a supplier will accept on a purchase order.

The minimum total dollar value a supplier requires for a purchase order to be accepted.

Gross Sales minus discounts and returns.

Units that have been ordered from a supplier but not yet received into inventory.

The dollar or unit amount still needed to purchase in a given period without exceeding the plan, calculated as: OTB = Planned EOM stock + Planned sales + Planned markdowns − Beginning stock (BOM) − Stock already on order. It's essentially the "budget remaining" for buyers to place new orders while staying aligned with the MFP.

The percentage of supplier orders delivered both on the agreed date and with the complete ordered quantity.

Inventory on hand that exceeds what's needed to cover forecasted demand through the planning period (lead time + days of cover), representing excess capital tied up in stock.

An earlier SKU whose sales history is used as the forecasting baseline for a newer replacement SKU.

A pre-configured assortment of sizes or colors bundled together as a single ordering unit, common in apparel.

A measure of how much unit demand shifts in response to changes in a product's price.

A signal that sales velocity slows meaningfully at or above a given price point, indicating the market is pushing back against further price increases.

The incremental demand a promotion generates above the baseline forecast — the units that would not have sold at full price.

Orders placed with suppliers to replenish inventory.

A 2x2 classification (e.g. velocity vs. margin) used to group SKUs into strategic buckets for replenishment prioritization.

A forecast that predicts a range of possible demand outcomes with probabilities (e.g. the 50th and 90th percentiles) rather than a single number, so safety stock and service levels can be set to a chosen confidence.

The system-generated order quantity suggested to meet forecasted demand through the next planning period.

The inventory level at which a replenishment order should be placed — typically expected demand over the lead time plus safety stock — so new stock arrives before the SKU runs out.

The configured rules — such as lead time, safety stock, and review cycle — that govern how replenishment recommendations are calculated for a SKU or category.

The total dollar value of merchandise sent back by customers during the period.

Returned Units divided by units sold, expressed as a percentage.

The number of units sent back by customers during the period.

Like MAE but squares each error before averaging, so large misses are penalized far more heavily. Useful when a few big errors (a spike or a stockout) matter most.

A buffer quantity held in addition to forecasted demand to protect against variability in demand or lead time.

The specific platform or storefront through which a sale occurred (e.g. DTC website, wholesale, Amazon, retail).

The average rate of units sold per day over the trailing 30-day period, typically excluding days the item was out of stock.

A repeating, calendar-driven pattern in demand (holidays, weather, back-to-school). A seasonal index scales the baseline forecast up or down by period to reflect it.

The price at which a unit is sold to the end customer.

Units sold during the period divided by (units sold + ending inventory) — the share of available stock that actually sold through.

The target probability of NOT stocking out during a replenishment cycle (e.g. 95%). It's the assumption that sets how much safety stock to hold — higher service level, more buffer.

A product that has sat in stock for an extended period with minimal sales velocity, signaling weak demand relative to the inventory invested in it.

The current physical quantity of a SKU held in inventory.

The monetary value of inventory on hand, calculated as units in stock × unit cost.

Beginning-of-period inventory divided by that period's sales — a planning ratio used in the Merchandise Financial Plan to set how much stock to receive and when.

A SKU/location with zero or negative available inventory, meaning it cannot fulfill demand until replenished.

A newer SKU designated to carry forward the sales history and forecast of a prior, now-discontinued SKU.

Total tax collected on sales during the period.

Net Sales plus taxes and any shipping charges — the full amount billed to customers.

A running measure of cumulative bias relative to average error, used to flag when a forecast has drifted out of line and needs re-tuning.

Orders that move inventory between warehouses or locations rather than ordering from a supplier.

Inventory on hand that falls short of what's needed to cover forecasted demand through the planning period, putting the SKU at risk of stocking out.

The cost paid to the supplier for a single unit, excluding freight and duties unless landed cost is used.

How many weeks current inventory will last at the current sales rate — the retail/apparel-standard cousin of Days of Cover, and the basis for stock-to-sales targets.

MAPE weighted by volume (total absolute error ÷ total actual units), so high-selling SKUs count more than slow ones. The more reliable headline accuracy number for a mixed catalog.