Tools to measure autism knowledge are needed to assess levels of understanding within particular groups of people and to evaluate whether awareness-raising campaigns or interventions lead to improvements in understanding. Several such measures are in circulation, but, to our knowledge, there are no psychometrically-validated questionnaires that…

Spearman's factor-analytic model has been proposed as a unidimensional linear item response theory (IRT) model for continuous item responses. This article first proposes a reexpression of the model that leads to a form similar to that of standard IRT models for binary responses and discusses the item indices of difficulty discrimination and…