The Judgment Gap three reasons more reviewers will not close it › Why adding a review gate buys less than it costs 12 steps, no labs
08 — part 3, three reasons more reviewers will not close itsourced

Why adding a review gate buys less than it costs

Sorting finished work at the end does not change what arrives at the end, and a gate is sorting.

The second reason, and it is older than this problem by decades. A review gate sorts what arrives at it. It does not change what arrives at it.

the gate sorts what arrives. It does not change what arrives before the gate the gate passed held and a while later, the stream arriving at the gate identical a gate is worth having. It is not a way to make less of this happen. which is the same argument that was made and won in manufacturing, long before anybody had this problem.
A gate is worth having. It is not a way to make less of this happen — the stream arriving at it is identical.
What moves: a stream with two bad items passes a gate and is sorted; a while later the stream arriving at the gate is drawn again and is unchanged.

Inspection at the end of a line sorts what arrives; it does not change what arrivesDeming, 1982unverified. That argument was made and won in manufacturing long before anybody had this problem, and it transfers cleanly: you cannot sort your way to a stream that needs less sorting.

It is worth being careful about what is and is not being claimed. Gates are useful. Catching a bad thing before it ships is better than not catching it. The claim is narrower: a gate moves work between two piles at the end, and the quantity this volume is about — how much gets produced without anybody judging it — is decided upstream of the gate and is not affected by it.

what a gate doeswhat it does not do
catches some of what is wrong before it shipsreduce how much wrong work is produced
gives you a count of what it caughttell you about what it did not catch, which is the remainder
makes the work that passes it more trustworthymake the work that bypasses it — because the gate has finite capacity — any more trustworthy

And a gate with finite capacity creates a bypass. That is the part people miss. When the gate cannot keep up, what actually happens is not that everything waits — it is that some things go around, chosen by whatever pressure is highest that week. So the gate's own capacity limit decides which work goes unexamined, and nobody designed that rule.

Every term this page uses

produced-to-examined
How much work your team produced, divided by how much of it somebody actually looked at.
examined
Looked at by somebody with enough context to have caught a problem. Not the same as having passed through a review step.
remainder
Work that was produced and not examined. It does not go anywhere — it merges into what everything after it is built on.
judgment
Deciding whether a piece of work is good, which needs knowing the domain well enough to recognize a wrong answer.
inspection
Checking finished work at the end, rather than changing how the work is made.
checkable
Able to be judged without understanding the whole of it. The property that decides how much needs judgment at all.
constraint
The thing that limits output. Adding more of anything else does not help until it moves.
rework
Work that had to be revisited after somebody called it done.
vigilance
Staying alert for a rare problem across a long stretch of time.

Taken as already known, and so not defined here: agent, model, review, throughput, headcount. That list is a claim about who is reading, and it is printed so it can be argued with.