Theory 087/Law & Forensic Science
Detection Is a Base Rate
The claim
The practical accuracy of deception detection is set by the base rate of deception rather than by test sensitivity.
01The mechanism
In a population where deception is rare, most positives are false; the same test performs differently across settings.
02Predictions
- P1Positive predictive value should track base rate.
- P2Sensitivity improvements should not fix low base rates.
03Refutation
Accuracy independent of base rate would remove the Bayesian term.