In the current study, the strength-based questionnaire Social-Emotional Assessment/Evaluation Measure (SEAM)--Research Edition was for the first time applied in a nationally representative sample of 0- to 6-year-old children. The focus of this study was the measurement properties of a Danish adaptation of SEAM. Rasch analysis was used to examine the criterion-related construct validity as well as accuracy and reliability of the measurement. The primary goal was to determine whether the 10 SEAM benchmarks could be combined into one total score or into a limited number of subscores. Data were collected by child-care providers in nonparental child-care facilities, and the response rate was high (95%; N = 9,827). The 10 benchmarks were successfully combined into two overall indexes: Empathy and Self-regulation & Cooperation. The reliability coefficients ranged from adequate (0.79) to excellent (0.94). However, standard errors of measurements were relatively large for the two indexes.