Lecture 3.6
A divergence is a fact. Whether it is a problem is a further claim requiring further evidence. This lecture separates detection from adjudication and sets the standard of proof required before an institution is told that its practice is causing harm.
Learning objectives
After this lesson, the reader should understand:
Concept framework
From divergence to verdict
Case study
Officers escalate at £48,000 against a documented £50,000. Is the drift harmful?
The divergence alone cannot answer it. Escalating earlier is more cautious, and caution is not self-evidently correct: it consumes review capacity, delays suppliers, and may deliver no measurable reduction in loss. The question is empirical — join the outcomes to the decisions, estimate the difference the tightening actually made, and adjust for the covariates that plausibly drive both the escalation and the outcome. Two disciplines apply. First, when many rules are examined at once, some will appear significant by chance alone, and the threshold must be corrected to account for that. Second, when the effect is small and the sample thin, the honest verdict is inconclusive — a category that must remain available, because a method that always returns an answer is not measuring anything.
Discussion questions
Exercise
Set the standard before you look.
Research notes