Differential Item Functioning on the International Personality Item Pool's Neuroticism Scale

As use of the public-domain International Personality Item Pool (IPIP) scales has grown significantly over the past decade (Goldberg, Johnson, Eber, Hogan, Ashton, Cloninger, & Gough, 2006) research on the psychometric properties of the items and scales have become increasingly important. This research study examines the IPIP scale constructed to measure the Five Factor Model (FFM) domain of Neuroticism (as measured by the NEO-PI-R) for occurrences of differential functioning at both the item and test level by gender and three age ranges using the DFIT framework (Raju, van der Linden, & Fleer, 1993) This study found six items that displayed differential item functioning by gender and three items that displayed differential item functioning by age. No differential functioning at the test level was found. Items demonstrating DIF and implications for potential scale revision are discussed.