What Is a History Bucket in Inventory Projection?

A history bucket is a period in an inventory projection whose dates already lie in the past, and it reports only the net of stock movements that actually happened in that period rather than anything that was planned for it. Forecast, firm demand, scheduled receipts, and replenishment suggestions are all switched off, so the left of the grid reads as recorded fact and the right reads as plan, joined by one continuous running balance.

This entry defines the history bucket and shows how it reads inside EDGEBIC by User Solutions. For the wider index of terms, see the manufacturing glossary; for the period concept it specializes, see what is a planning bucket in MRP; and for the running balance it contributes to, see EDGEBIC projected available balance explained.

How It Works

An inventory projection rolls a balance forward one bucket at a time. In a normal future bucket, the arithmetic takes the balance carried in, adds the supply expected to arrive, subtracts the demand expected to consume it, and carries the result into the next bucket. Forecast and firm demand combine into a gross requirement, scheduled receipts supply the other side, and a replenishment suggestion may appear when the result dips below a trigger.

A history bucket runs the same roll-forward with most of those inputs zeroed. Scheduled receipts are set aside. Gross requirements are set aside. What remains is the realized net movement for the period, which is the signed sum of the ledger entries that actually posted in it: positive where receipts outweighed issues, negative where they did not. That single figure is added to the carried balance, and the result carries forward.

Replenishment suggestions are suppressed too. Advising an order for a period that has already closed is advice nobody can act on, so the suggestion column stays empty on history rows and only wakes up once the buckets reach the present.

The reasoning behind suppressing planned supply in the past is worth stating plainly. A scheduled receipt is a claim about the future. If a build was due last Tuesday and slipped, it never reached the shelf, and showing it in last Tuesday's bucket would display stock the plant did not have. The receipt is not lost: it now sits in whichever future bucket its current completion date falls in. Counting it once, in the right place, is the whole discipline.

A Concrete Example

A planner reaches the projection horizon back three weeks to review how the last month actually went for a stocked part.

The three history buckets show only realized movement. Week one nets plus 180, because a build receipt landed and only light issues went out. Week two nets minus 240, a heavy consumption week with no arrivals. Week three nets minus 60. The running balance walks down accordingly, and the last history bucket hands its closing figure to the first future bucket as its opening balance.

Week two is where the plan and the record diverge. The plan had shown a 200-unit receipt in that week, and the history bucket shows none, because the build slipped. Looking at the future buckets confirms it: the receipt now appears next week, where its current completion date lands. Nothing has been lost or double counted, and the reason the forward projection is tighter than expected is now visible on one screen.

None of the three history rows carries a replenishment suggestion, which is correct. The forward rows do, and that is where the planner acts.

How EDGEBIC Uses It

In EDGEBIC, a projection bucket is treated as history when its period ends before today, and history is what you get by setting the horizon start earlier than the current date. Leave the horizon starting today and the grid is pure forward plan with no history rows at all.

On a history row, the balance moves by the realized net of ledger entries for that period alone. Planned supply and computed gross requirements contribute nothing, and the replenishment suggestion is held at zero. Every one of those figures comes from the inventory ledger, which is the append-only record of what actually moved, so a history bucket is as trustworthy as the postings behind it.

There is a related subtlety worth knowing when you reach the horizon back. The opening balance of the window is computed as of the window start, but the available-to-promise calculation deliberately starts from physical stock as it stands now rather than from that historical opening. Promising capacity has to reflect the shelf today, not the shelf three weeks ago, so the two figures legitimately differ whenever the window begins in the past.

Read history buckets as diagnosis rather than instruction. They tell you why the forward plan looks the way it does, and the levers that change the outcome live in the future rows.

For the movements that fill a history bucket, see what is an inventory adjustment and what is a scheduled receipt in MRP. For the value the window starts from, see what is an opening balance in inventory.