A Note on Inferential Decisions, Errors and Path-Dependency

Abstract: Consider the standard sequential testing of a binary outcome. The associated belief process and its objectively true conditional-probability counterpart generally differ, but they converge to the same target in well-defined tests. We show that unless the two processes are 'essentially identical', differing at most by an a priori factor, time-homogeneous continuous sequential decisions based on the former must be path-dependent with respect to state-variables based on the latter or other non-essentially-identical belief processes. Further, total inferential errors decompose into two components with distinct and independent characteristics.