Face Memory and Face Matching: Internal Consistency and Test-Retest Reliability for the CFMT+ and the GFMT-S

The Cambridge Face Memory Test Long (CFMT+) and the Glasgow Face Matching Test Short (GFMT-S) are frequently used tests in face recognition research. No test-retest results in conjunction with internal consistency, mean inter-item correlations (MICs), and pre-post mean differences have been reported. The internal consistency and the MICs provide insights into the homogeneity of items. In an online study (N = 72), we investigated the test-retest reliability, Cronbach's α, split-half reliability, MICs, and retest mean differences for the CFMT+ and the GFMT-S. The CFMT+ showed satisfactory reliability coefficients above .88, whereas the coefficients of the GFMT-S were mainly dissatisfactory and below .75. We argue that task characteristics like heterogeneous stimulus material might lower MICs, response behavior might enhance reliability, and practice effects might increase the means of the CFMT+ in repeated measurements. Therefore, an integrative evaluation of different psychometric parameters helps explaining variations of reliability in face recognition tests.