What Is Direction Precedence in Scheduling? EDGEBIC Definition

Direction precedence is the fixed order that decides which scheduling path an order takes when several rules could apply: anchor, then actuals, then planned-start pins, then backward, then forward. The engine evaluates the list top to bottom for each order, and the first applicable rule wins. A bottleneck anchor is harder than a due date; started work always continues forward from its resume point; planner pins express forward intent; only a genuinely new job with a real due date runs backward; and everything else is plain forward scheduling. It is how EDGEBIC keeps the plan consistent when a job carries more than one intention at once.

This entry is part of the EDGEBIC by User Solutions glossary series; for the broader vocabulary of planning, see the manufacturing glossary. For the underlying choice of direction, see forward versus backward scheduling.

How Direction Precedence Works

An order can carry several signals about how it should be scheduled. It may route through a bottleneck the engine anchors around. It may have steps already started. It may carry planner pins. It may be a new order with a due date that suggests backward scheduling. Each of these implies a different scheduling path, and they can point in different directions.

Direction precedence resolves the conflict with a single ordered rule set. The engine checks, in order:

1. Anchor. If the order routes through a bottleneck work center, anchor scheduling governs it: the constraint is scheduled first, with work placed backward to feed it and forward to ship from it.
2. Actuals. If any step has recorded actual dates, the job continues forward from its current state; started work is a fact and is never un-started.
3. Planned-start pins. If a step carries a durable planned-start pin, the engine schedules forward from the pinned date, honoring the planner's stated intent.
4. Backward. If none of the above apply and the order is a new job with a real due date, the backward pass right-aligns it to finish just in time.
5. Forward. Otherwise the job schedules forward from its start time, the default.

The first rule that applies decides the path; the rest are skipped for that order. Every rule that lost is recorded in the session diagnostics, so a planner can always see why a given job took the path it did.

A Concrete Example

Picture the dinner-party version. You planned to put the roast in the oven as late as safely possible so it comes out hot at seven, a backward, just-in-time intention. But the roast is already in the oven; you started it early because the guests arrived. At that point start as late as possible is moot. The roast is cooking, and all you can sensibly do is keep going from where it is.

The engine treats a started job the same way. A new backward job right-aligns to its due date, but the moment a step has actuals, the actuals rule outranks backward, and the engine continues forward from the resume point rather than pretending the work has not begun. Anchor outranks even that: if the roast has to come out to make room for the constraint dish at exactly seven, that timing governs everything around it. The ordered list makes the outcome predictable instead of leaving it to chance.

How EDGEBIC Uses It

Direction precedence is baked into how the engine schedules each order, and it shows up in the tools around scheduling:

• The engine resolves the path per order by walking anchor, actuals, pins, backward, forward, and taking the first that applies. This is why a bottleneck-routed job ignores its due-date direction and an in-progress job never tries to schedule backward.
• The session diagnostics record the losers. Every rule that could have applied but was outranked is logged, so a planner can trace exactly why a job forward-scheduled when they expected it to run backward.
• Backward is deliberately low. Because backward sits below anchor, actuals, and pins, opting a job into backward scheduling never overrides a constraint or started work; it only governs a clean, new, due-dated job.

Direction precedence is the referee that decides when the anchor step rule, actuals, or backward scheduling governs a job. To set the underlying intent on a specific order, see how to schedule a job backward from its due date, and remember that precedence still decides whether that intent actually applies.