Evidence Commons^™

Dna, Blue Bus, And Phase Changes, Edward K. Cheng, G. Alexander Nunn

Faculty Scholarship

In ‘Exploring the Proof Paradoxes’, Mike Redmayne comprehensively surveyed the puzzles at the intersection of law and statistics, the most famous of which is the Blue Bus problem, which prohibits legal actors from ascribing liability purely on the basis of probabilistic evidence. DNA evidence, however, is a longstanding exception to Blue Bus. Like Blue Bus, DNA presents probabilistic evidence of identity. Unlike Blue Bus, DNA is widely accepted as legitimate, even when it stands alone as so-called ‘naked’ statistical evidence. Observers often explain such DNA exceptionalism in two ways: either that people break down in extreme cases, or relatedly, that …