A test of the International Personality Item Pool representation of the Revised NEO Personality Inventory and development of a 120-item IPIP-based measure of the five-factor model.

There has been a substantial increase in the use of personality assessment measures constructed using items from the International Personality Item Pool (IPIP) such as the 300-item IPIP-NEO (Goldberg, 1999), a representation of the Revised NEO Personality Inventory (NEO PI-R; Costa & McCrae, 1992). The IPIP-NEO is free to use and can be modified to accommodate its users' needs. Despite the substantial interest in this measure, there is still a dearth of data demonstrating its convergence with the NEO PI-R. The present study represents an investigation of the reliability and validity of scores on the IPIP-NEO. Additionally, we used item response theory (IRT) methodology to create a 120-item version of the IPIP-NEO. Using an undergraduate sample (n = 359), we examined the reliability, as well as the convergent and criterion validity, of scores from the 300-item IPIP-NEO, a previously constructed 120-item version of the IPIP-NEO (Johnson, 2011), and the newly created IRT-based IPIP-120 in comparison to the NEO PI-R across a range of outcomes. Scores from all 3 IPIP measures demonstrated strong reliability and convergence with the NEO PI-R and a high degree of similarity with regard to their correlational profiles across the criterion variables (rICC = .983, .972, and .976, respectively). The replicability of these findings was then tested in a community sample (n = 757), and the results closely mirrored the findings from Sample 1. These results provide support for the use of the IPIP-NEO and both 120-item IPIP-NEO measures as assessment tools for measurement of the five-factor model.