Ask a plant what a job produced and you usually get one number. Ask what it was supposed to produce and you get another. The distance between those two numbers is where most of the interesting information about a production process lives, and it is also the part most often left undocumented. This page is about that distance: how it becomes visible, what the quantities inside it are called, and why keeping them apart matters more than a tidy single figure.
The BOM already says what the job should produce
Before anything is made, the expected output quantity for a job is already defined. It comes from the bill of materials, which sets out both what goes into a product and how much of that product a given set of inputs is meant to produce.
That number does a quiet amount of work. Without a stated expectation there is nothing for the actual result to be compared against, and a production figure on its own can only be reported, never assessed. How the bill of materials is structured is covered in material structure and multi-level BOM. What matters here is narrower: the BOM defines an expected output quantity, and it exists before the job runs.
What production actually delivered
The second number arrives at the other end. When output is received from production, the actual quantity received is recorded against the job.
Recording it as a distinct fact, rather than assuming the job produced what it was told to, is the basis of everything that follows. Where the expected figure is carried forward as if it were the result, shortfalls do not disappear; they migrate, turning up as stock that does not reconcile or as a month-end investigation through shift registers. The quantity was always missing. What was missing was any record of it being missing.
This is also where the boundary with planning sits. Deciding what to make, checking material availability and releasing the job belong to production planning and material requirement. This page starts once production has run and something has come back.
Yield is what the comparison produces
With both numbers in place, yield stops being an opinion. exactllyERP compares the actual output received with the output quantity the BOM defines and shows the resulting yield percentage.
Yield here is not something anyone selects from a list or maintains by hand. It is derived from the comparison, and exists because both sides of it exist. That distinction matters when evaluating any system: a yield figure somebody enters reports an opinion, while one that falls out of a comparison is a consequence of the record.
Yield is available by product, by production stage, by work centre and by period. Those are four different questions: whether a particular item consistently returns less than the BOM anticipates, where in the process the loss concentrates, whether it follows a machine or a team, and whether anything changed last quarter actually worked. A single plant-wide yield number answers none of them.
The difference still has to go somewhere
A percentage tells you how large the gap is, not what it was made of. That is the question an operator, a production manager and a buyer all eventually ask.
Where the actual output received does not match the output quantity the BOM defines, exactllyERP asks the user to record the applicable quantities that explain the difference. These may include scrap, reusable material, rework material and by-product. Which are relevant depends on what happened: two processes do not fail in the same way, and neither is obliged to use categories the other needs.
The words are worth separating, because in ordinary conversation they collapse into a general sense of waste.
| Resulting quantity | What it means operationally | What happens next |
|---|---|---|
| Actual output received | The quantity that came back from the job as usable output | Carries on as the main result of the job |
| Reusable material | Quantity that remains usable as material rather than as finished output | Retained as its own quantity and available for subsequent use |
| Rework material | Quantity intended to receive further work before it can be accepted | Handled as a rework question; the exception itself is a separate subject |
| Scrap | Quantity that will not return to the main output path | Recorded, and available for disposal or reuse |
| By-product | A secondary output produced alongside the main one | Retained as its own quantity and available for subsequent use |
Yield is deliberately absent from that table. It is not one of these quantities: it describes the relationship between what was expected and what was received, which is a different kind of fact.
More than one of them can apply at once
This is the assumption most worth abandoning. A production result does not have to be reduced to one finished quantity. More than one resulting category may apply to the same production result, and a separate quantity can be recorded for each one that does.
Take an illustration, with round numbers chosen to show the shape rather than any particular job. A BOM defines an expected output of a hundred units. Production returns ninety-four as actual output received. Six units are unaccounted for by that figure alone, and they are what needs explaining. In one operation that might all be recorded as scrap. In another, part might be reusable material and the rest rework material. Where the process also produces a secondary output, a by-product quantity may be recorded as well.
The illustration is about the shape of the record, not arithmetic. There is no prescribed combination, no category that must always appear, and nothing here to be read as a formula. The categories let the difference be described in terms that fit what happened.
Keeping the quantities apart afterwards
Recording a quantity separately is only half of it. The other half is whether it stays separate.
Resulting quantities can be stored in separate warehouses, keeping them operationally distinct, and those stored quantities can subsequently be used as required. For scrap specifically, the public manufacturing description is more particular: scrap inventory is updated, and the scrap is available for disposal or reuse.
The reason to bother is practical. A quantity returned to a general location has, for most purposes, stopped existing as a separate thing. Nobody can say how much there is, whether it is accumulating, or whether it is worth acting on. Keeping it in its own place preserves all three answers, and that choice is genuinely difficult to revisit a year later. Moving a quantity somewhere else should not cost you the knowledge of what it is either, which is the subject of batch and lot traceability.
Why rejection rate and yield are not the same thing
These two figures get quoted interchangeably in review meetings, and they are not measuring the same thing. Rejection is recorded when output is not accepted at the point it is checked: an event, mid-process, at a stage. Yield reflects what the job finally delivered against what the BOM said it should: an outcome, at the end.
The gap between them is not an error. A quantity rejected at an operation may be reworked and become usable output, in which case it appeared in the rejection figure and never became a final shortfall. Another may become scrap, and shows up in both. So a plant can reduce its rejection rate without moving yield by the same amount, and the reverse happens too.
Both numbers are worth having. Rejection tells you where quality is being lost during the process; yield tells you what production ultimately returned. How rejection itself is recorded, including the reason behind it and how rework stays connected to the job it came from, belongs to rejection and rework tracking. What any of these quantities is worth is a different subject again, and belongs to work-order costing and variance.
What to make an ERP vendor demonstrate
This subject demonstrates well, because it is difficult to fake with a clean run. The wider evaluation method is set out in the ERP selection and evaluation guide; the sequence below is the one specific to production output.
- Start from the BOM and show the expected output quantity for a job before it runs.
- Record an actual output received that is deliberately different from that expectation.
- Show the resulting yield percentage, and ask to see yield by product, by stage, by work centre and by period.
- Record more than one resulting quantity against the same production result, and check each is retained separately rather than merged.
- Show scrap, reusable material, rework material and by-product quantities as distinct figures.
- Store the resulting quantities in different warehouses and show what subsequent use of them looks like.
Then ask what the system does not do, because that is where assumptions hide. How exactly is the yield percentage arrived at? Is there a standard or target yield to compare against? Is process loss recorded separately from scrap? Where do financial values get attached, and by whom? These are good questions precisely because the answers differ between systems.
How exactllyERP handles production output
In exactllyERP, the output quantity defined on the BOM is used as the expected output for the job, and the actual output received from production is recorded against it. The two are compared, and the resulting yield percentage is shown.
Where the actual output received does not match the BOM-defined output quantity, exactllyERP asks the user to record the applicable quantities that explain the difference, including scrap, reusable material, rework material and by-product. More than one of these categories may apply to the same production result, and a separate quantity is retained for each. Those resulting quantities can be stored in separate warehouses and used subsequently as required.
Yield is available by product, by production stage, by work centre and by period for review. Scrap inventory is updated, and scrap is available for disposal or reuse. The broader manufacturing workflow this sits inside is described on the manufacturing ERP page, and the functional scope across procurement, inventory, production and finance on the features page.
This page describes capability, not configuration. Which resulting categories a process needs, where each quantity is stored, and who classifies a difference when it appears are implementation choices. They are worth deciding before go-live, because a difference that was never classified cannot be classified retrospectively.
Common questions
How is production yield determined in exactllyERP?
It comes from a comparison rather than from a figure somebody types in. The BOM already defines the output quantity a job is expected to produce. When output is received from production, the actual quantity received is recorded against the job. exactllyERP compares the two and shows the resulting yield percentage. That is worth being precise about: yield is not an output category anyone selects, and not a number anyone maintains by hand. It is what the comparison produces once both sides of it exist.
What happens when actual output does not match the BOM output quantity?
The difference is not left as an unexplained gap. Where the actual output received does not match the output quantity the BOM defines, exactllyERP asks the user to record the applicable quantities that explain the difference. These may include scrap, reusable material, rework material and by-product. Nothing obliges a job to use all of them, or any particular combination of them. The point is that the difference is described when it is known rather than reconstructed later from memory.
Can one production result contain more than one type of resulting quantity?
Yes. More than one resulting category may apply to the same production result, and a separate quantity can be recorded for each one that does. This is the part most often assumed away. A production result is frequently treated as a single finished number with everything else rounded into it, which is exactly what makes a shortfall hard to explain three weeks later. Keeping the quantities apart is what allows each of them to be seen for what it is.
What is the difference between scrap, reusable material, rework material and by-product?
They differ in what can happen to the quantity next. Scrap will not return to the main output path, though it may still have operational use. Reusable material remains usable as material. Rework material is intended to receive further work. A by-product is a secondary output produced alongside the main one rather than a shortfall in it. They are not interchangeable words for waste, and recording them as one figure loses the distinction that makes each of them actionable.
Can these quantities be kept in separate warehouses?
Yes. Resulting quantities can be stored in separate warehouses, keeping them operationally distinct, and those stored quantities can subsequently be used as required. On the public manufacturing description, scrap inventory is updated and is available for disposal or reuse. What suits a particular operation is an implementation decision worth settling deliberately, because a quantity returned to a general location tends to stop being visible as a separate thing.
Is rejection rate the same as production yield?
No, and treating them as the same causes avoidable arguments. Rejection is recorded when output is not accepted at the point it is checked. Yield reflects what the job finally delivered against what the BOM said it should. A quantity rejected mid-process may be reworked and go on to become usable output, so an early rejection does not automatically become a final shortfall. The two figures answer different questions: one is about where quality is being lost, the other about what production ultimately returned.
Where to start
Take one product where the plant suspects the output does not match what the BOM says it should, and where the explanation has always been anecdotal. Write down what the BOM expects, what production typically returns, and what people believe accounts for the difference. That last part is the revealing one, because it tends to be several different explanations depending on who is asked.
If exactllyERP is on your shortlist, bring that product to the demonstration and ask to see the difference recorded in categories rather than described.