Early Childhood Measurement Invariance of the Strengths and Difficulties Questionnaire Across Age, Race, Sex, and Socioeconomic Status

Research suggests there are differences in children’s internalizing and externalizing symptoms as a function of age, race, sex, and socio-economic status (SES). Males, Black children, and children experiencing lower SES have been rated as having more externalizing problems. Female and older children have been rated as having higher internalizing symptoms. The validity of these findings rests on the assumption that the measures mean the same thing across groups and developmental time (i.e., Measurement Invariance; MI). Without assuring MI, results may represent differences in measurement and not true differences in the underlying construct. The Strengths and Difficulties Questionnaire (SDQ) is a widely used tool to measure internalizing and externalizing symptoms. Papers have evaluated MI of the SDQ in school-aged children. However, to our knowledge, no studies of young children have examined MI across Black and White families from diverse SES backgrounds. Data from the Family Life Project were used to evaluate MI of the SDQ across child age (35 to 90 months), race, sex, and SES. Using moderated non-linear factor analysis (MNLFA), multiple SDQ items demonstrated measurement non-invariance as a function of child demographic variables. Results suggest that it is important to test and adjust for non-invariance with the SDQ when applied to early-childhood populations comprising Black and White children from diverse SES backgrounds. An MNLFA approach improves our ability to validly measure and compare symptoms of psychopathology in diverse early childhood populations. This could have implications for our understanding of rates of mental health challenges and treatment in early childhood.