A meta-analysis of criterion effects for the Implicit Relational Assessment Procedure (IRAP) in the clinical domain.
OBJECTIVE
The Implicit Relational Assessment Procedure (IRAP) is a technique that is attracting a substantial body of research literature, particularly within the clinical domain.


METHODS
In response, the present paper outlines a meta-analysis of clinically-focused IRAP effects (N = 494) to provide the first estimate of how well such effects validate against their respective criterion variables in general.


RESULTS
The meta-analysis incorporated clinically-focused IRAP effects from 15 studies yielding a large effect size, r¯ = .45, with a desirably narrow 95% credibility interval (.23, .67). The funnel plot and subsequent sensitivity analyses indicated that this meta-effect was not subject to publication bias.


CONCLUSIONS
The present meta-effect is an estimate based upon an IRAP literature that is still evolving rapidly in the clinical domain, and so as per its accompanying credibility interval, all conclusions that follow are necessarily provisional even if bounded. Apart from the fact that the current meta-effect might be subject to inadvertent under- and/or over-estimations of the current literature, the present meta-effect might strengthen with further refinements of the IRAP.


CONCLUSIONS
The current meta-effect provides the means to calculate what sample size would be required to achieve a statistical power of .80 when testing the criterion validity of clinically-focused IRAP effects using a given parametric statistic. For example, first-order Pearson correlations would hypothetically require an N of 29-37 for such purposes depending upon how conservatively over-estimation of the present meta-effect is controlled for. Overall, the IRAP compares favourably with alternative implicit measures in clinical psychology.
Department of Psychology, Maynooth University, Maynooth, Co. Kildare, Ireland. Electronic address: nigelvahey@gmail.com.
Nigel A
NA
Vahey
Department of Psychology, Maynooth University, Maynooth, Co. Kildare, Ireland. Electronic address: Emma.Nicholson@nuim.ie.
Emma
E
Nicholson
Department of Psychology, Maynooth University, Maynooth, Co. Kildare, Ireland. Electronic address: Dermot.Barnes-Holmes@nuim.ie.
Dermot
D
Barnes-Holmes
D001290:Attitude; D003627:Data Interpretation, Statistical; D006801:Humans; D009483:Neuropsychological Tests / Q000592:standards*; D011594:Psychometrics / Q000592:standards*; D012107:Research Design / Q000592:standards*
Clinically-focused; Criterion effects; IRAP; Meta-analysis; Statistical power