Exploratory factor analysis with principal components using varimax rotation was conducted in SAS 9.3 to examine the underlying dimensional structure of the TOCS. We also conducted promax rotation because of the expected correlation of TOCS items. Phenotypic correlations between the OC trait dimensions were examined using Pearson’s correlations with IBM SPSS Statistics 21.0. We assigned items to factors when the factor loading was > 0.7 and had factor loadings < 0.4 for all other factors. We considered scree plots, cumulative variance explained and interpretability when selecting the number of factors.
