Accurate psychological measurements remain challenging due to the symptoms’ latent and subjective nature. Standard instruments for assessing generalized anxiety and depression, such as the GAD-7 and PHQ-9, typically rely on Likert scaling. This study examined Borg centiMax (cMax) adaptations of these measures to study whether ratio-scaled response formats retain the psychometric properties of the originals. Adults from a convenience sample (N = 138) completed Likert and cMax multi-item (MI) of the GAD-7 and PHQ-9, a single-item (SI) cMax global measure of GAD and MDD, and life satisfaction. Analyses assessed internal consistency, convergent and divergent validity, and discriminative validity. Both cMax MI and Likert formats showed good to excellent internal consistency. Strong convergence between cMax and Likert measures of general anxiety (r = .73–.77) and depression (r = .79−.86), indicated preserved construct coverage. Divergent validity was supported by moderate associations with life satisfaction (r = −.44 to −.63). ROC analyses showed good-to-excellent MI and SI cMax discrimination of clinically relevant anxiety and depression (sensitivity = .82–.92; specificity = .76–.93). Both formats also distinguished between participants who did or did not recognize themselves in the descriptions of GAD and MDD. MI and SI formats performed comparably, with MI aligning slightly more closely with traditional scales. We conclude that the centiMax-based instruments retained the psychometric and structural properties of the original scales while providing a ratio-scaled, standardized response format that may enhance interpretability and cross-domain comparability in psychological assessment.
Borg et al. (Thu,) studied this question.