title: Application of generalizability theory in estimating the reliability of ankle-complex laxity measurement.
abstract: BACKGROUND
  Generalizability theory is an appropriate method for determining the reliability of measurements obtained across more than a single facet. In the clinical and research settings, ankle-complex laxity assessment may be performed using different examiners and multiple trials.
  
  
  OBJECTIVE
  To determine the reliability of ankle-complex laxity measurements across different examiners and multiple trials using generalizability theory.
  
  
  METHODS
  Correlational study.
  
  
  METHODS
  Laboratory.
  
  
  METHODS
  Forty male university students without a history of ankle injury.
  
  
  METHODS
  Measures of right ankle-complex anteroposterior and inversion-eversion laxity were obtained by 2 examiners. Each examiner performed 2 anteroposterior trials, followed by 2 inversion-eversion trials for each ankle at 0 degrees of ankle flexion. Using generalizability theory, we performed G study and D study analyses.
  
  
  RESULTS
  More measurement error was found for facets associated with examiner than with trial for both anteroposterior and inversion-eversion laxity. Inversion-eversion measurement was more reliable than anteroposterior laxity measurement. Although 1 examiner and 1 trial had acceptable reliability (G coefficient >/= .848), increasing the number of examiners increased reliability to a greater extent than did increasing the number of trials.
  
  
  CONCLUSIONS
  Within the range of examiner and trial facets studied, any combination of examiners or trials (or both) above 1 can change ankle laxity measurement reliability from acceptable (1 examiner, 1 trial) to highly reliable (3 examiners, 3 trials). Individuals may respond to examiners and their procedural nuances differently; thus, standardized procedures are important.
authors.affiliation: University of South Alabama, Department of Health & Physical Education, 307 North University Boulevard, Mobile, AL 36688-0002, USA. bheitman@usouthal.edu
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Heitman
authors.forename: John E
authors.initials: JE
authors.lastname: Kovaleski
authors.forename: Steven F
authors.initials: SF
authors.lastname: Pugh
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D000843:Ankle Joint / Q000503:physiopathology*; D053587:Arthrometry, Articular; D006801:Humans; D007593:Joint Instability / Q000503:physiopathology*; D008297:Male; D015203:Reproducibility of Results; D013223:Statistics as Topic; D055815:Young Adult