The present research aimed at constructing a questionnaire measuring overclaiming tendencies (VOC-T-bias) as an indicator of self-enhancement. An approach was used which also allows estimation of a score for vocabulary knowledge, the accuracy index (VOC-T-accuracy), using signal detection theory. For construction purposes, an online study was conducted with N = 1,176 participants. The resulting questionnaire, named Vocabulary and Overclaiming – Test (VOC-T) was investigated with regard to its psychometric properties in two further studies. Study 2 used data from a population representative sample (N = 527), and Study 3 was another online survey (N = 933). Results show that reliability estimates were satisfactory for the VOC-T-bias index and the VOC-T-accuracy index. Overclaiming did not correlate with knowledge, but it was sensitive to self-enhancement supporting the construct validity of the test scores. The VOC-T-accuracy index in turn covaried with general knowledge and even more so with verbal knowledge, which also supports construct validity. Moreover, the VOC-T-accuracy index had a meaningful correlation with age in both validation studies. All in all, the psychometric properties can be regarded as sufficient to recommend the VOC-T for research purposes.
Estimation of an accuracy index of a diagnostic biomarker when the reference biomarker is continuous and measured with error
