Generalizability studies of the Global Assessment of Functioning-Split version.
OBJECTIVE
The study aimed to use the Generalizability Theory to investigate the reliability and precision of the split version of the Global Assessment of Functioning (GAF).


METHODS
Six case vignettes were assessed by 2 samples; one by 19 experienced and independent raters and another by 58 experienced raters from 8 different day-treatment units, evaluating both symptom and function scores of GAF.


METHODS
Generalizability studies were conducted to disentangle relevant variance components accounting for error variance in GAF scores. Furthermore, decision studies were conducted to estimate the reliability of different measurement designs, as well as precision in terms of error tolerance ratio.


RESULTS
Both symptom and function scores of GAF were found to be highly generalizable, and a measurement design of 2 raters per subject was found to be most efficient with respect to reliability, precision, and use of resources.


CONCLUSIONS
Both symptom and function scores of GAF seem highly consistent across experienced raters.
Pedersen
Geir
G
Department of Personality Psychiatry, Ullevål University Hospital, 0407 Oslo, Norway. geir.pedersen@medisin.uio.no
Hagtvet
Knut Arne
KA
Karterud
Sigmund
S
D003071:Cognition; D003657:Decision Making; D005793:Generalization, Psychological; D006801:Humans; D001523:Mental Disorders / Q000453:epidemiology* / Q000523:psychology / Q000628:therapy*; D008960:Models, Psychological; D015588:Observer Variation; D011582:Psychological Theory; D012153:Retention, Psychology; D011795:Surveys and Questionnaires; D016896:Treatment Outcome