Forced-choice Five Factor markers

The Big Five Questionnaire (Brown & Maydeu-Olivares, 2011) was developed in the context of a study researching item response theory (IRT) modeling of forced-choice questionnaires. The purpose of the questionnaire is to measure the Big Five personality factor markers. Items were drawn from the 100 items of the International Personality Item Pool. The authors selected 60 items so that 12 items would measure each of the five marker traits, with 8 positively and 4 negatively keyed items per trait combined in a way that equal number of pairwise comparisons occur between items keyed in the same direction and items keyed in opposite directions. Each block of the questionnaire was presented in two formats. First, participants rated the three items using a 5-point rating scale, ranging from "very accurate" to "very inaccurate." This single-stimulus presentation was immediately followed by the forced-choice presentation, where the participants were asked to select one "most like me" item and one "least like me" out of the same block of three items. A total of 438 volunteers from the United Kingdom completed the questionnaire online. The reliability estimates ranged from .775 to .844 for the single-stimulus data and from .601 to .766 for the forced-choice data. The maximum a posteriori estimated trait scores for individuals based on single-stimulus and forced-choice responses correlated strongly, with correlations ranging from .69 for Agreeableness to .82 for Extraversion.