Limitations
Despite the fact that the psychometric analysis sample was broad and representative of the end user population, the study did encompass some limitations. Specifically, the sample size for (70 subjects for the psychometric validation) could have been larger although similar sample sizes have been used for other tools PGI/CGI items were developed specifically for use as anchor measures in the psychometric evaluation of the OST 2.0 due to lack of existing measures that would be appropriate for these analyses. However, the PGI/CGI items were qualitatively tested prior to use to ensure patients understood the items as intended, and the items were developed in line with FDA guidance. Additionally, comparisons of the DET and OST 2.0 scores were drawn to confirm that the new OST 2.0 measures the same concepts as the DET score but with the aim of being more sensitive.Finally, different types of correlations were used in the analyses based on the type of data included. Although this follows guidelines it may be harder to draw comparisons across correlations. Factor analysis was not performed to evaluate dimensionality due to sample size limitations and the complexity of the instrument.