Psychometric properties of the self-report version of the strengths and difficulties questionnaire in the Ecuadorian context: an evaluation of four models

This study evaluates the psychometric properties of four models of the Strengths and Difficulties Questionnaire (SDQ) in a sample of 1470 children and adolescents from Biblian, Ecuador. The instrument has been used by researchers and students. However, there are not reports that show that the instrument is valid or reliable in the Ecuadorian context. Reliability was evaluated through Cronbach’s Alpha, McDonald’s Omega, Intra-class Correlations and Greatest Lower Bound (GLB). Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA) with polychoric correlation matrix and Diagonally Weighted Least Square (DWLS) estimator is performed in each model. Due to possible readability problems, CFA was performed in three age groups. Measurement invariance analysis across biological sex and two groups of age is carried out. CFA and reliability analysis revealed poor construct validity of the original version of SDQ. Three additional factor structures were tested. A version that includes a prosocial subscale, and internalizing subscale and an externalizing subscale has the best yet insufficient construct validity properties among the four models (CFI = .858, TLI = .844, RMSEA = .055, WRMR = 1.588). Cronbach’s Alpha for the subscales ranged from .44 to .71, McDonald’s Omega from .22 to .606, GLB from .612 to .693, and ICC from .385 to .63. Measurement invariance analysis found no evidence of invariance across sex groups and evidence of partial invariance across age groups. The four tested models have questionable psychometric properties. Consequently, the use of the SDQ in the Ecuadorian context is not advisable. The three-factor first-order model of the SDQ that shows the best validity and reliability properties does not have undisputed psychometric properties. Comparisons across groups of age and/or sex using the SDQ should not be made.