Voting and Sincerity - Ideal Point Drift and Strategy in a Regulatory Board

We use a dynamic item response theory model (Martin and Quinn 2002) to investigate ideal point stability in Mexico's IFE, an election regulatory board. Results indicate that stability is not predominant, that most board members moved considerably a good deal of the time. We discuss how theories of representation view movement and show that some of the drift we detected is in fact associated with systematic factors. Evidence suggests that movement and strategic considerations associated with representation correlate, contradicting the standard assumption of sincere voting