Modeling forced-choice response formats

To counter response distortions associated with the use of rating scales in personality and similar assessments, test items may be presented in so-called ‘forced-choice’ formats. Respondents may be asked to rank-order a number of items, or distribute a fixed number of points between several items – therefore they are forced to make a choice. Until recently, basic classical scoring methods were applied to such formats, leading to scores relative to the person’s mean (ipsative scores). While interpretable in intra-individual assessments, ipsative scores are problematic when used for inter-individual comparisons. Recent advances in estimation methods enabled rapid development of item response models for comparative data, including the Thurstonian IRT model (Brown & Maydeu-Olivares, 2011a), the Multi-Unidimensional Pairwise Preference model (Stark, Chernyshenko & Drasgow, 2005), and others. Appropriate item response modeling enables estimation of person scores that are directly interpretable for inter-individual comparisons, without the distortions and artifacts produced by ipsative scoring.