Test-Retest Reliability of the HEXACO-100 – and the Value of Multiple Measurements for Assessing Reliability

Despite the widespread use of the HEXACO model as a descriptive taxonomy of personality traits, there remains limited information on the test-retest reliability of commonly-used inventories to measure its traits. Studies typically report internal consistency estimates, such as alpha or omega, as measures of reliability, but there are good reasons to believe that these do not accurately assess reliability. Therefore, we report 12-day test-retest correlations of the 100- and 60-item English HEXACO-Personality Inventory-Revised (HEXACO-100 and HEXACO-60) domains, facets, and items. In order to test the validity of test-retest reliability, we then compare these estimates to correlations between self- and informant- reports (also known as cross-rater agreement), a widely-used validity criterion, as well as to domain and facet internal consistencies. Median estimates of test-retest reliability were .88, .81, and .65 (N = 416) for domains, facets, and items, respectively. Facets' and items' test-retest reliabilities were highly correlated with their cross-rater agreement estimates, whereas alphas were not. Overall, the HEXACO-Personality Inventory-Revised demonstrates test-retest reliability similar to other contemporary measures. We recommend that short-term retest reliability should be routinely calculated to assess reliability.