What a certificate does and does not tell you
Exams measure recall and recognition across a broad syllabus. They are a reasonable floor. They say little about how someone investigates, prioritises or communicates during a failure, because the format cannot observe it.
Observe the work
The most direct assessment is to give an engineer a broken system and watch what they do. The fix matters, but so does the path: what they checked, in what order, what they changed and whether they confirmed the result.
Make it comparable
An assessment a manager can use needs a few properties.
- The same starting state for everyone who takes it.
- A fixed time limit, so results are comparable.
- A record of actions, not only a pass or fail.
- Failures across several kinds of work, so one strength does not hide a gap.
Use it for development, not only hiring
Repeated over time, the same kind of assessment shows where a team is getting stronger and which kinds of failure nobody on it has practised yet.