Process cycle efficiency
Value-added time as a share of lead time. Single-digit percentages are normal, which is the point of drawing the map.
Formula
In practice
Process cycle efficiency divides value-added time by total lead time, and on a first current-state map it is usually a single-digit percentage. That is not a defect in the measurement — it is the finding. Value-added time is mix-weighted on the same basis as process time, so it is a share of the same quantity rather than a figure computed against a different denominator.
The diagnostic rule fires below 5% by default, and that threshold is a judgement about a plant rather than a constant: a job shop and a high-volume line disagree about what counts as poor. It is overridable, and the set of thresholds actually used comes back on the report. The finding carries no quantified impact on purpose — low PCE is real and there is no defensible number to attach to it, and inventing one would be worse than leaving it out.
How this is calculated
Common questions
What is a good process cycle efficiency?
The tool declines to publish a target, because the answer depends on the stream. What it does is fire a finding below 5% by default and let you move the threshold, with the threshold you used printed on the report so a reader can disagree with it.
Is value-added time the same as processing time?
Not necessarily. Processing time is every cycle on the route; value-added time is the part of it the customer would pay for. Where a study has not distinguished them the two coincide, and the efficiency figure should be read as an upper bound.
Related terms
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Lead time
How long one piece takes to travel the whole stream, waiting included. Measured along the critical path, so parallel…
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Total inventory
Everything sitting between the processes, counted in pieces, and the biggest component of lead time on most maps.
This definition is the one the product itself shows, read from its interface catalogue at build time.