A Two-Decision Model for Responses to Likert-Type Items

Extreme response set, the tendency to prefer the lowest or highest response option when confronted with a Likert-type response scale, can lead to misfit of item response models such as the generalized partial credit model. Recently, a series of intrinsically multidimensional item response models have been hypothesized, wherein tendency toward extreme response set is simultaneously estimated alongside one or more psychological constructs of interest. The multidimensional nominal response model (MNRM) is a divide-by-total model that allows person parameters for response sets, including extreme response set. The proportional thresholds model (PTM) is a difference model with response set parameters. The present study introduces a two-decision model (TDM) as an alternative to the MNRM and PTM and compares all three on data from assessments used in employee selection.