title: Validity of the strengths and difficulties questionnaire in preschool-aged children.
abstract: BACKGROUND
  The Strengths and Difficulties Questionnaire (SDQ) is widely used to screen for child mental health problems and measure common forms of psychopathology in 4- to 16-year-olds. Using longitudinal data, we examined the validity of a version adapted for 3- to 4-year-olds.
  
  
  METHODS
  We used SDQ data from 16,659 families collected by the Millennium Cohort Study, which charts the development of children born throughout the United Kingdom during 2000-2001. Parents completed the preschool SDQ when children were aged 3 and the standard SDQ at ages 5 and 7. The SDQ's internal factor structure was assessed by using confirmatory factor analysis, with a series of competing models and extensions used to determine construct, convergent, and discriminant validity and measurement invariance over time. Predictive validity was evaluated by examining the relationships of age 3 SDQ scores with age 5 diagnostic measures of attention-deficit/hyperactivity disorder, autism spectrum disorder/Asperger syndrome, and teacher-reported measures of personal, social, and emotional development.
  
  
  RESULTS
  Confirmatory factor analysis supported a 5-factor measurement model. Internal reliability of subscales ranged from ω = 0.66 (peer problems) to ω = 0.83 (hyperactivity). Item-factor structures revealed measurement invariance over time. Strong positive correlations between ages 3 and 5 SDQ scores were not significantly different from correlations between age 5 and 7 scores. Conduct problems and hyperactivity subscales independently predicted developmental and clinical outcomes 2 years later.
  
  
  CONCLUSIONS
  Satisfactory psychometric properties of the adapted preschool version affirm its utility as a screening tool to identify 3- to 4-year-olds with emotional and behavioral difficulties.
authors.affiliation: Psychology Department, s.e.croft@sheffield.ac.uk.
authors.forename: Simone
authors.initials: S
authors.lastname: Croft
authors.affiliation: Institute of Work Psychology, University of Sheffield, Sheffield, United Kingdom; and.
authors.forename: Christopher
authors.initials: C
authors.lastname: Stride
authors.affiliation: Social Genetic & Developmental Psychiatry Research Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom.
authors.forename: Barbara
authors.initials: B
authors.lastname: Maughan
authors.affiliation: Psychology Department.
authors.forename: Richard
authors.initials: R
authors.lastname: Rowe
mesh_terms: D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D001523:Mental Disorders / Q000175:diagnosis*; D011594:Psychometrics; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires / Q000592:standards*
keywords: average variance explained; factor structure; factorial invariance; parent-reported SDQ; preschool; psychometrics; validity