the station / sector 01
Feedback latency
How to tell where you areDo not ask how good your tests are. Ask when you last learned about a defect, and who told you. If the answer is a customer, a support ticket, or a dashboard you happened to be looking at, you are at the bad end of this line no matter what your coverage report says.
How long between writing a defect and finding out you wrote it.
This is the axis to move first, and the reason is arithmetic rather than taste. Every other improvement you make will be made wrong at least once. The cost of making it wrong is roughly the time you spend not knowing — the code you pile on top of the mistake, the other changes that land in the same window and have to be untangled from it, the context you have to rebuild when the report finally arrives. Shortening that interval discounts every future mistake, including the mistakes you make adopting everything else on this site.
It is also the axis people misdiagnose most often. A team with a four-hour CI run and a team with no tests at all both describe their problem as “our tests are bad”, and the two need opposite interventions.