Toward meaningful digital measures: efficiency as a core concept of interest

This was a presentation made at the CTAX (Clinical Trials in Inherited Ataxias) conference. It makes the argument that behavioral efficiency is a core "concept of interest" in ataxias that has relevance across ataxia diagnoses, disease stages, and behavioral domains. Furthermore, in the context of evaluating efficacy in an interventional trial, it contends that increasing the efficiency of natural, everyday behaviors, is inherently and objectively meaningful for ataxias. Examples of digital measures are provided to demonstrate how they capture movement efficiency, thereby supporting their meaningfulness.