Linking the Child Behavior Checklist to the Strengths and Difficulties Questionnaire

The Child Behavior Checklist (CBCL) and Strengths and Difficulties Questionnaire (SDQ) both measure emotional and behavioral problems in children and adolescents, and scores on the two instruments are highly correlated. When administrative needs compel practitioners to change the instrument used or data from the two measures are combined to perform pooled analyses, it becomes necessary to compare scores on the two instruments. To enable such comparisons, we score linked three domains (Internalizing, Externalizing, and Total Problems) of the CBCL and SDQ in three age groups spanning 2–17 years. After assessing linking assumptions, we compared item response theory (IRT) and equipercentile linking methods to identify the most statistically justifiable link, ultimately selecting equipercentile linking with loglinear smoothing due to its minimal bias and the ability to link raw SDQ scores with both T-scores and raw scores from the CBCL.