Getting The ‘Correct’ Answer From Survey Responses: A Simple Application Of The Em Algorithm

This note addresses a problem that can arise in surveys, namely when some respondents misinterpret the rating method and so assign high ratings when they intended to assign low ratings, and vice versa. We present a method that allows these misinterpretations to be corrected with high probability, and more meaningful conclusions to be drawn. The method is illustrated with data from a Community Value survey.