From Visibility to Reconstructability: A Programme for Measuring Decision Accountability in Human–AI Systems

This working paper describes a research programme addressing a structural failure in AI governance documentation: mandatory reporting frameworks produce records that are visible but not reconstructable — that can be inspected but do not support independent recovery of the decision pathway that produced an outcome. The paper introduces the Boundary Transparency Index (BTI), a six-field scoring instrument operationalising reconstructability as a measurable property of any decision record, and reports empirical findings from three mandatory reporting corpora (California DMV AV disengagement, N=2,500; NHTSA SGO, N=1,473; CFPB complaints, N=25,000) and an independent human rater study (N=60 matched pairs, Cohen's dz=2.451, p