ShipStream Knowledge Base
Warehouse Setup

Slotting Density

Slotting Density compares picking activity with the space used by each Product. Within each Warehouse, Lane and Merchant population, ShipStream converts the selected density formula into a Slotting Density Rank (SDR) from 0 through 1000. A higher SDR means greater activity per unit of space, and Products with equal density receive the same rank.

The Slotting Density report records the population-level outcomes after each completed calculation, so you can compare changes over time and identify missing geometry before relying on the figures. Select a population to review its individual Product scores.

Understand ShipStream: Who Gets First Choice?

The Product picked most often is not necessarily the best use of a preferred Location. One may generate many visits from a small assigned space; another may move many units on each visit. ShipStream's Rank Formula lets you choose which relationship matters:

  • Slotting Density compares pick visits with the Product's committed space, the volume of its assigned pick faces, even when those faces are empty.
  • Burn Efficiency compares net units picked with single-unit volume. It emphasizes unit throughput relative to Product size.
  • Pick Density compares pick visits with single-unit volume. It emphasizes visit frequency relative to Product size.

Each formula produces a relative SDR within the same Warehouse, Lane, and Merchant. During Directed Put-Away, higher-ranked Products get first choice among the remaining eligible Locations, after open replenishment needs have been handled. The rank does not override feasibility or change a Product's stocking target.

Switch formulas in the example, then change a Product's inputs. The highlighted fields show exactly what drives the selected score. A different Product leads under each formula in the starting example; there is no single formula that is best for every operation.

Who gets first choice?1 · Observe
Rank Formula
First choice: Towels.

Favors pick activity relative to the space already assigned. Switching formulas changes priority, not stocking targets.

Independent synthetic example · 21-day observation window · One Warehouse, Lane and Merchant

Observed Product data

Marked fields drive the selected score.

CableAwaiting rank
pick visits · used
420
net units picked
2,100
single-unit ft³
0.05
committed ft³ · used
4
Observed inputs above—visits / committed ft³
HeadphonesAwaiting rank
pick visits · used
840
net units picked
840
single-unit ft³
0.08
committed ft³ · used
12
Observed inputs above—visits / committed ft³
TowelsAwaiting rank
pick visits · used
630
net units picked
1,260
single-unit ft³
0.4
committed ft³ · used
3
Observed inputs above—visits / committed ft³

Best eligible Locations first

Remaining lines choose in rank order.

  1. A-01 · Priority 1 / first choice
    Awaiting placement
    ready to placenot assigned yet
  2. A-02 · Priority 2 / second choice
    Awaiting placement
    ready to placenot assigned yet
  3. A-03 · Priority 3 / third choice
    Awaiting placement
    ready to placenot assigned yet

Each incoming line fits any of these Locations. Location Priority decides which Location is best: its Priority while it holds the Product, otherwise its Default Priority. Pick Route order only sequences the tour's stops.

Feasibility, active homes and open replenishment needs come first. This scene starts after those decisions.

Same inputs, different priorities. Pick visits and units picked describe different kinds of activity. Single-unit volume and committed space are also different measurements.

A visit can move one unit or many. Used by Slotting Density and Pick Density.

Throughput, not visit frequency. Used only by Burn Efficiency.

One Product unit, not its entire pick face. Used by Burn Efficiency and Pick Density.

Assigned pick-face volume, even when empty. Used only by Slotting Density.

Compare Slotting Density, Burn Efficiency, and Pick Density using the same Products and activity. Change the inputs to see how relative ranks and placement priority change.This is an independent example with a 21-day observation window, positive activity, and complete geometry above the unit-volume guard. Every incoming line fits each illustrated destination. SDR is a relative rank, not an efficiency percentage; equal scores share a rank, and this example uses Product order to break placement ties. The controls recalculate immediately for comparison. ShipStream normally refreshes ranks on the scheduled calculation or a requested recomputation.

These formulas answer who gets first choice, not how much stock to carry. Understand stocking targets to compare equal-space, equal-time, and tailored DOI settings.

Configure Slotting Density

Slotting Density settings can be configured independently for each Warehouse:

  1. Navigate to System -> Configuration.
  2. Choose the Warehouse under Warehouses in the Current Configuration Scope menu.
  3. Navigate to Warehouse -> Stock -> Slotting Density.
  4. Set the fields below and click Save Config.
FieldDescription
Rank FormulaThe ratio used to rank Products in each population. The default is Slotting Density.
Observation Window DaysThe number of complete Warehouse-local days included in each calculation. The default is 21, and the allowed range is 1 through 365. The window ends with yesterday, so a partial current day never changes the result.
Neutral SDRThe fallback rank used when ShipStream cannot derive an observed rank, including a Product with no pick visits, a singleton population, incomplete committed geometry, or a Product that has been assigned to a Lane but not yet slotted. The default is 500, and the allowed range is 0 through 1000.
Unit Cube GuardThe smallest reliable single-unit cube for formulas that use a Product's unit cube. It is displayed in the installation's base volume unit and defaults to the same physical volume as 1 cubic inch.

Saving these settings does not queue a recalculation. The nightly calculation is the normal refresh mechanism; a super administrator can use Queue Recompute when the next publication is needed sooner.

See Configuration Scope for more information about Warehouse-specific settings.

Choose the rank formula

FormulaRatioWhen to use it
Slotting Density (pick visits ÷ committed space)Pick visits divided by the Product's committed forward-pick volumeThe default. It rewards activity relative to the space currently assigned to the Product.
Burn Efficiency (units ÷ unit cube)Net units picked divided by one Product unit's cubeCompares physical throughput. Cancel and revert corrections remain attached to the original pick day.
Pick Density (pick visits ÷ unit cube)Pick visits divided by one Product unit's cubeCompares how often a Product is visited relative to its physical size.

Changing the formula does not immediately rebuild the report. Use Queue Recompute when an immediate refresh is needed; otherwise the nightly rebuild uses the new setting.

Unit cube and guard

Burn Efficiency and Pick Density require a reliable single-unit cube. ShipStream looks for it in this order:

  1. The Product's Storage Dimensions, but only when all three fields are filled with valid positive values. An incomplete set is never mixed with the general dimensions; if any of the three values is missing or not positive, the general Product dimensions are used for all axes instead.
  2. The Product's general dimensions and volume when no complete Storage Dimensions set applies.
  3. A confirmed quantity-BOM unit-of-measure cube, divided by its base quantity, only when the Product has no usable dimensions of its own.

Storage Dimensions belong to the Product and are not configured per Warehouse. Enter them in the Storage Dimensions fields under the General tab of the Product page; they use the global base length unit shown beside the fields and are not converted.

The Unit Cube Guard is displayed in the installation's base volume unit. Its default is always the same physical volume as 1 cubic inch, including installations that display cubic centimetres or cubic millimetres. A resolved cube equal to or above the guard is eligible. A missing cube or one below the guard is not clamped; the Product receives the neutral SDR and appears as Excluded: unit cube.

The guard has no effect when Slotting Density is selected.

Open the report

Navigate to Operations -> Slotting Density.

Each row represents one published calculation for a Warehouse, Lane and Merchant. The report retains historical publications for at least 90 days and initially filters Published At to the last 30 days. Change that filter to view an earlier publication.

You can filter and sort the report by any displayed field. Use the Export control to download the current filtered view as CSV or Excel. Volume exports keep the measurement in a numeric column and place its unit in the following column.

Access is controlled by the System -> Operations -> Slotting Density role permission. The report also respects the Warehouses and Merchants available to the administrator.

Read the report

In this report, a face is an eligible forward-pick Location. Space means volume, not floor area, and is displayed in the configured volume unit.

  • Published At shows when the complete calculation became available. Until another calculation publishes, the previous result remains the current result.
  • Warehouse, Lane and Merchant identify the population measured by the row. Merchants are always calculated separately.
  • Observation Start and Observation End show the complete Warehouse-local days included in the activity totals.
  • Forward-Pick Space is the total volume of non-temporary, pickable Locations in the Lane's destination Location Profile, including Locations that are not currently assigned to a Product.
  • Committed Space is the forward-pick volume assigned to the Merchant's Products in that Lane. A face remains committed regardless of the quantity currently stored in it.
  • Space Committed (%) is Committed Space divided by Forward-Pick Space, expressed as a percentage. It measures how much of the total forward-pick space has been assigned to this Merchant's Products.
  • Pick Visits is the gross number of visits to pickable source Locations during the observation window. It counts visits, not units picked.
  • Demand Lines is the number of demand lines recorded over the same observation window.
  • Pick Visits per volume and Demand Lines per volume divide the activity totals by Committed Space, using the volume unit configured for display.
  • Geometry Status is Complete only when both Forward-Pick Space and Committed Space can be calculated without omitting a Location. Otherwise it is Incomplete.
  • Forward-Pick Locations Missing Geometry counts eligible forward-pick Locations whose physical volume is unknown.
  • Committed Locations Missing Geometry counts Product-assigned Locations whose committed space is unknown.
  • Cohort Revision identifies the published calculation. A higher revision for the same Warehouse, Lane and Merchant is a newer calculation.
  • Rank Formula identifies the formula used to rank Products in the publication.
Space Committed (%) is not an inventory-fill percentage. It measures forward-pick space assigned to Products, not how much inventory physically occupies those Locations at the moment.

When Geometry Status is Incomplete, ShipStream leaves any affected space, percentage committed, and activity-per-volume values blank rather than presenting a partial figure as complete. Use the missing-geometry counts to determine whether the missing geometry belongs to the Lane generally, to assigned Product faces, or both. Review the affected Locations and ensure their Slot Types have valid physical dimensions.

When Committed Space is zero and geometry is otherwise complete, Space Committed (%) is 0%. Activity-per-volume values remain blank because there is no committed space to divide by.

Review Product results

Select a report row to review its Product results. The Product report includes:

  • SDR, the percentile score used by directed put-away
  • SDS, pick visits divided by committed space
  • BER, signed net units divided by single-unit cube
  • the selected Rank Formula
  • the reason for neutral or excluded results

The report shows the last completed publication. Formula and guard values are recorded with each publication, so historical results retain the settings that produced them.

Queue a recompute

The recompute controls are available only to super administrators.

  1. Navigate to Operations -> Slotting Density.
  2. Under Recompute Slotting Density, choose a Warehouse.
  3. Choose one Merchant, or leave All merchants selected.
  4. Click Queue Recompute.

ShipStream confirms that the recompute request was queued. Discovery and recalculation run in the background; if the selected scope has no eligible active cohort, no new report rows will appear.

Recomputation runs in the background. Existing report rows remain available while it runs, and the new historical row appears only after the complete cohort publishes.