Item response theory is a set of models and methods allowing for the analysis of binary or ordinal variables (items) that are influenced by a latent variable or latent trait- that is, a variable that cannot be measured directly. The theory was originally developed in educational assessment but...

Labor economists regularly regress educational achievement scores on covariates to examine what aects achievement. I discuss the mea surement and interpretation of achievement scores, and argue that, as the scores are typically measured on an ordinal scale, their analysis in terms of higher...

Economists regularly regress IQ scores or achievement test scores on covariates, for example to evaluate educational policy. These test scores are ordinal measures, and their distributions can take an arbitrary shape, even though they are often constructed to look normal. The ordinality of test...

Surveys are widely used by scholars, companies, and public policymakers to generate invaluable insights. Despite the popularity of surveys, there are several biases that can affect the validity of self-reported data. In his inaugural address, Martijn de Jong discusses how new survey methods can...

An unfolding model for continuous bounded responses is proposed, derived both from a hypothetical interpolation response mechanism and from the hypothesis of two opposite sources of item refusal being collapsed. These two sources of refusal are made explicit in a three-component Dirichlet...

This paper takes a close look at material deprivation in 27 European Union countries. Its main goal is to explore which expenditures individuals/households curtail first when facing economic difficulties. Two methodologies are applied: item response theory, a psychometric method also known as...

If standard two-parameter item response functions are employed in the analysis of a test with some newly constructed items, it can be expected that, for some items, the item response function (IRF) will not fit the data well. This lack of fit can also occur when standard IRFs are fitted to...