Difficulty abandoning a mindset once formed, even after the evidence that produced it has been discredited. The judgement persists after its foundation is gone — and the analyst experiences the persistence as expertise rather than as inertia. Related terms in the literature: mindset, mental set, perseverance of beliefs.
In intelligence analysis
- A judgement is built on a source that is later retracted; the conclusion often survives the retraction, because it has been absorbed into the picture and now feels supported by everything else.
- Where a previous finding is carried into a new product without restating its uncertainties, the impression is left that the claim is better founded than the evidence allows — the "layering effect" in assessments.
- Perseverance is strongest where the analyst has publicly committed to the judgement, which is why it shades into Overconfidence Bias and escalation of commitment.
- It explains why painstaking re-validation of sources produces so little movement in the assessed picture: the sources move, the judgement does not.
Countermeasure
- Key Assumptions Check at the point of re-issue, not only at the point of first assessment.
- Track which judgements rest on which sources, so that retracting a source visibly invalidates the judgement rather than quietly leaving it standing.
Related
- Cognitive Bias — the taxonomy this bias sits within
- Confirmation Bias — supplies the continuing support for an already-formed view
- Structured Analytic Techniques — assumption checks and ACH as the structural counter
- Anchoring Bias — the initial judgement becomes the anchor it never departs from