An Initial Analysis of Reliability and Validity of a Personality Instrument Using the Rasch Measurement Model

Abstract

This study aims to provide empirical evidence of validity and reliability of a personality instrument using the Rasch Measurement Model. Data was collected from 53 samples from a public university using the 5-Point Likert scale IPIP-NEO 120 (Johnson, 2014) questionnaire. Analysis using Rasch Measurement Model is attained through summary statistics, unidimensionality analysis and persons-items fit measures. Statistically, results from the study have shown that the items in the instrument have a high degree of validity and reliability; therefore, suitable for the measurement of personality characteristics among Malaysians. Premised on the concept item response theory, the Rasch Measurement Model is an ideal mean for instrument validation.