Validity of the Strengths and Difficulties Questionnaire for Screening and Diagnosis in Western Australian Adolescents

BACKGROUND/OBJECTIVES

The Strengths and Difficulties Questionnaire (SDQ) is a widely used 25-item screening and diagnostic tool for behavioral and emotional problems in young people. Despite its popularity, evaluations of the SDQ's factor structure in adolescent populations have produced disparate results, and its relationships with theoretically related variables are rarely evaluated. In the present study, these two elements of validity were evaluated based on a large sample of Western Australian adolescents.

METHODS

Participants were 1489 adolescents, n = 623 males with a mean age of 13.79 years (SD = 1.61) and n = 866 females, with a mean age of 14.29 years (SD = 1.51). Participants completed the SDQ alongside measures of loneliness, sense of belonging, depression, bullying, and diagnostic status to evaluate its internal structure and correlations with theoretically related variables.

RESULTS

Confirmatory factor analyses supported the internal structure of the SDQ both for males and for females. Relationships between the SDQ subscale scores and those from theoretically related variables were also aligned with the instrument's underpinning framework.

CONCLUSIONS

Despite the somewhat disparate results of previous studies, overall, this study supported the validity of the SDQ for use in the Western Australian context.

The revised Edward Zigler Yale-Personality Questionnaire (EZPQ) for persons with intellectual disability: A new four-factor structure in confirmatory factor analysis

Zigler’s theory assumes that due to frequent negative personal experiences, persons with intellectual disability are likely to develop specific personality traits which hinder their functioning. The Edward Zigler-Yale Personality Questionnaire (EZPQ) is a measure that allows these traits to be assessed. However, studies in which the measure was used report problems with its factorial structure and reliability. We evaluated the psychometric properties of EZPQ in three consecutive studies conducted in three different samples of 336, 330, and 310 students with mild and moderate intellectual disability. By making successive modifications to the original version of the EZPQ, we developed and validated a revised four-factor version of the questionnaire that consists of 16 items (EZPQ-16R). The factors we identified corresponded to the following traits: readiness to explore, assignment alacrity, negative-reaction tendency, and support dependence. The reliability of the new gauge was high, and its validity was confirmed in correlational analyses with other measures of personality and adjustment. The four traits that were identified are directly derived from Zigler’s theory, thus giving a new perspective on the assessment of specific personality traits in persons with intellectual disability.