title: Application and Evaluation of an Expert Judgment Elicitation Procedure for Correlations.
abstract: The purpose of the current study was to apply and evaluate a procedure to elicit expert judgments about correlations, and to update this information with empirical data. The result is a face-to-face group elicitation procedure with as its central element a trial roulette question that elicits experts' judgments expressed as distributions. During the elicitation procedure, a concordance probability question was used to provide feedback to the experts on their judgments. We evaluated the elicitation procedure in terms of validity and reliability by means of an application with a small sample of experts. Validity means that the elicited distributions accurately represent the experts' judgments. Reliability concerns the consistency of the elicited judgments over time. Four behavioral scientists provided their judgments with respect to the correlation between cognitive potential and academic performance for two separate populations enrolled at a specific school in the Netherlands that provides special education to youth with severe behavioral problems: youth with autism spectrum disorder (ASD), and youth with diagnoses other than ASD. Measures of face-validity, feasibility, convergent validity, coherence, and intra-rater reliability showed promising results. Furthermore, the current study illustrates the use of the elicitation procedure and elicited distributions in a social science application. The elicited distributions were used as a prior for the correlation, and updated with data for both populations collected at the school of interest. The current study shows that the newly developed elicitation procedure combining the trial roulette method with the elicitation of correlations is a promising tool, and that the results of the procedure are useful as prior information in a Bayesian analysis.
authors.affiliation: Department of Methods and Statistics, Utrecht University Utrecht, Netherlands.
authors.forename: Mariëlle
authors.initials: M
authors.lastname: Zondervan-Zwijnenburg
authors.affiliation: Schreuder College Location Villeneuvestraat, Horizon Jeugdzorg en Onderwijs [Horizon Youth Care and Education] Rotterdam, Netherlands.
authors.forename: Wenneke
authors.initials: W
authors.lastname: van de Schoot-Hubeek
authors.affiliation: Department of Methods and Statistics, Utrecht University Utrecht, Netherlands.
authors.forename: Kimberley
authors.initials: K
authors.lastname: Lek
authors.affiliation: Department of Methods and Statistics, Utrecht UniversityUtrecht, Netherlands; CITO Institute for Educational MeasurementArnhem, Netherlands.
authors.forename: Herbert
authors.initials: H
authors.lastname: Hoijtink
authors.affiliation: Department of Methods and Statistics, Utrecht UniversityUtrecht, Netherlands; Optentia Research Focus Area, North-West UniversityPotchefstroom, South-Africa.
authors.forename: Rens
authors.initials: R
authors.lastname: van de Schoot
keywords: Bayesian analysis; correlation; elicitation procedure; expert judgment; informative priors