What Is Backlog in Capacity Scheduling? EDGEBIC Definition

Backlog is the forward sum of remaining hours a work center still owes as of a given period. In EDGEBIC by User Solutions, each work-center-and-day cell of the Resource Calendar shows the hours of booked work still ahead of that machine, so a step burns down 24 to 16 to 8 to 0 across periods as it is worked off. Backlog is a running tally of what a resource still has to do, not a count of incoming orders, and it tells a planner how deep the queue is in front of each machine.

This entry is part of the EDGEBIC glossary series. For the broader vocabulary, see the manufacturing glossary. Backlog sits alongside the load and utilization view of a resource; for how EDGEBIC computes the percentage version, see the Work Center Utilization report.

How Backlog Works

Backlog answers a question no single capacity number does: at this moment, how much work is still sitting in front of this machine? A utilization percentage tells you how full a period is, but backlog tells you the size of the queue that keeps building or draining as time passes.

The key detail is how the hours are stored. The Resource Calendar's Backlog mode keeps hours per allocation-day, so the number in each cell is the forward sum of the remaining hours as of that period. As a step is worked off, its contribution shrinks. A 24-hour job does not sit at 24 in every period it touches; it reads 24, then 16, then 8, then 0 as it burns down, which is the true picture of what is left to do.

That is the change from the mode it replaced. The former Load view repeated a step's full hours in every period until the step completed, so the same 24-hour job showed 24, 24, 24 and made the machine look permanently swamped. Backlog fixed the count while keeping the internal key the same, so existing screens still work but the number finally means "remaining," not "full duration repeated." For a planner, that is the difference between a queue depth they can trust and one that cries wolf.

A Concrete Example

Take Mill-1 with a single 24-hour job booked to start Monday and run across the week.

Under the current Backlog mode, the daily cells read:

By Wednesday, Mill-1 still has 8 hours of that job ahead of it. Click the Wednesday cell and the Job Detail popup opens, listing the remaining allocations that make up the 8 hours; under the same job and shift filters those rows sum exactly to 8.

Now compare the retired Load logic on the same job: it would have painted 24, 24, 24 through Wednesday, implying three days of full load where there was really one job draining down. The Backlog view shows the machine clearing, which is what a planner needs to decide whether it can take the next job.

How EDGEBIC Uses Backlog

Backlog is a mode of the Resource Calendar, not a separate report pane, but planners reach for it alongside the reporting catalog. It is the view you open to see how deep the queue runs in front of each work center over the coming periods, and to spot where a machine clears versus where the remaining hours never fall. The related walkthrough how to see a work center's load for next month in EDGEBIC covers reading the calendar for forward capacity.

The drill-down is what makes backlog actionable. Because every Backlog cell opens the Job Detail popup and reconciles to the underlying allocations, you are never left with an unexplained number. That pairing of a summary figure and a traceable detail is the same discipline EDGEBIC applies across its reporting, from the column glossary on every report to the Backlog cell you can click straight through to the jobs behind it.