Social skills are necessary for developing successful relationships and promoting learning. "Interpersonal skills" (IPS) are needed for maintaining friendships while "learning-related skills" (LRS) are required for positive classroom behaviours. In this study, we investigated the construct validity of LRS and IPS within two existing assessments: the "Child Behavior Rating Scales" (CBRS) and the "Preschool and Kindergarten Behavior Scales--2nd edition" (PKBS-2). Teachers completed the CBRS and PKBS-2 for 117 Singaporean children aged 3-6 years. Rasch analysis was used to identify items that fit the unidimensional constructs of LRS and IPS within each instrument. Specific items from within the CBRS were found to measure LRS and IPS. Within the PKBS-2, items were found to measure IPS and a new construct labelled "Compliance". Instead of creating new assessment tools to measure new constructs, this study innovatively demonstrated how Rasch analysis can be used to document the existence of new constructs within already existing tools. The identification of new constructs and the use of these tools in an Asian context are presented. (Contains 2 notes and 5 tables.)