title: The short Working Alliance Inventory in parent training: Factor structure and longitudinal invariance.
abstract: The purposes of the present study were twofold: (a) to examine the factor structure of the Working Alliance Inventory, Short (WAI-S) and (b) to investigate if factor loadings and thresholds fulfilled properties of longitudinal measurement invariance across two waves of data.
  
  
  
  The study sample consisted of 259 Norwegian parents receiving Parent Management Training, the Oregon model. Parents rated alliance at sessions 3 and 12 during the therapy. Confirmatory factor analyses to assess the fit of a one-, two-, and three-factor model were performed using robust weighted least squares estimation for categorical indicators.
  
  
  
  The results showed that data provided best fit for the three-factor solution with goal, task, and bond. Furthermore, results demonstrated satisfactory invariance for factor loadings and thresholds across time.
  
  
  
  Overall, the results indicate that the WAI-S three-factor solution has acceptable psychometric properties for longitudinal measurement comparisons.
authors.affiliation: a The Norwegian Center for Child Behavioral Development, Unirand , University of Oslo , Oslo 0306 , Norway.
authors.forename: Silje S
authors.initials: SS
authors.lastname: Hukkelberg
authors.affiliation: a The Norwegian Center for Child Behavioral Development, Unirand , University of Oslo , Oslo 0306 , Norway.
authors.forename: Terje
authors.initials: T
authors.lastname: Ogden
mesh_terms: D000328:Adult; D019958:Attention Deficit and Disruptive Behavior Disorders / Q000628:therapy*; D002648:Child; D002675:Child, Preschool; D004505:Education, Nonprofessional / Q000379:methods* / Q000592:standards; D005163:Factor Analysis, Statistical; D005196:Family Therapy / Q000379:methods* / Q000592:standards; D005260:Female; D006801:Humans; D008297:Male; D017063:Outcome Assessment, Health Care / Q000379:methods* / Q000592:standards; D010290:Parents / Q000193:education; D011369:Professional-Patient Relations; D011594:Psychometrics / Q000295:instrumentation*
keywords: Parent Management Training; WAI-S; factor structure; longitudinal invariance; working alliance