Unexamined work never announces itself
Work nobody looked at does not go anywhere or complain. It merges into what everything after it is built on.
The reason this can run for a year without anybody raising it is that unexamined work is not a pile somewhere. It went out. It is in production, or in a document somebody is relying on, or in a decision that has already been made on top of it.
So there is nothing to find. Work that nobody examined and that happened to be fine is indistinguishable, from the outside, from work that was examined. Work that nobody examined and that was not fine looks like the first kind until something built on top of it fails.
The absence of a complaint is not evidence
| what people take as reassurance | what it actually establishes |
|---|---|
| nothing has gone wrong | that nothing has gone wrong yet, at this level of the system |
| customers have not noticed | that the failures so far have been of a kind customers do not see |
| the tests pass | that what somebody thought to test still behaves |
| the reviewers have not flagged anything | that the share of work reaching a reviewer has not produced flags. Not what happened to the rest |
Every row in that right-hand column is a true and much smaller statement than the left. None of them is about the remainder, and the remainder is the quantity that grew.
And there is no instrument you can buy for it. You cannot detect unexamined work by looking at outputs, because unexamined work that happens to be correct looks exactly like examined work. The only way to know the share is to count what was examined, which is the arithmetic in the previous step and the reason it comes before the evidence.