title: Strategies to manipulate reliability: impact on statistical associations.
abstract: OBJECTIVE
  To examine the effects of improving measurement reliability on associations between risk factors and childhood psychiatric disorder.
  
  
  METHODS
  Data were from a general population sample of parents (N = 211) with children aged 6 to 16 years. Reliability of measurement was improved in three ways: by increasing the number of items in a scale (internal-consistency reliability), by averaging assessments of the same variables collected on two different occasions, and by constructing latent variable measures. To assess the effects of improving reliability, selected risk factors were regressed on parental assessments of childhood oppositional defiant disorder (ODD) and overanxious disorder (OAD).
  
  
  RESULTS
  Improving reliability led to systematic increases in the magnitude of standardized regression coefficients between family dysfunction and ODD (beta = .30-.51) and between family dysfunction and OAD (beta = .24-.48). In multiple regression, improving reliability served to strengthen the specificity of associations between ODD, OAD, and family dysfunction and maternal depressed mood. Although latent variable methods produced the largest associations, the standard errors of these estimates were also larger, resulting in wider confidence intervals and slightly larger significance values.
  
  
  CONCLUSIONS
  Improving reliability of measurement results in larger associations between risk factors and childhood disorder and may increase the opportunity of revealing differential associations between variables.
authors.affiliation: McMaster University, Hamilton, Ontario, Canada.
authors.forename: M H
authors.initials: MH
authors.lastname: Boyle
authors.forename: A R
authors.initials: AR
authors.lastname: Pickles
mesh_terms: D000293:Adolescent; D001008:Anxiety Disorders / Q000175:diagnosis* / Q000523:psychology; D019958:Attention Deficit and Disruptive Behavior Disorders / Q000175:diagnosis* / Q000523:psychology; D002648:Child; D003863:Depression / Q000175:diagnosis / Q000523:psychology; D005195:Family Relations; D005260:Female; D006801:Humans; D008297:Male; D009035:Mothers / Q000523:psychology; D010552:Personality Assessment / Q000706:statistics & numerical data*; D011594:Psychometrics; D015203:Reproducibility of Results; D012307:Risk Factors