A critical review of the validity of the Credibility Assessment Tool (CAT) and its application to the screening of suspected malingering

Theunissen, Karen Sunette (2011-03)

Thesis (MOccTher)-- University of Stellenbosch, 2011.

Thesis

ENGLISH ABSTRACT: Malingering, the intentional simulation or exaggeration of symptoms for secondary gain, has a significant financial impact on disability insurance given its prevalence. Multidisciplinary professionals involved in disability determination therefore require a tool which would assist in the screening of suspected malingerers. AIM: The Credibility Assessment Tool (CAT), a tool which was developed as part of the Performance APGAR, was reviewed in terms of its validity and application to the screening of malingering. Research objectives included the review of face and content validity through a literature review and concept analysis, as well as the review of construct and concurrent validity by comparing the results with the operationalised malingering construct and available malingering protocols. The adapted Slick criteria as proposed by Aronoff, applicable to chronic pain, neurocognitive, neurological and psychiatric symptoms, was identified as the most suitable criterion standard for use of comparison. DESIGN: The research design was a descriptive analytical design, which was performed retrospectively with a report review from insurance referrals to the researcher. Informed consent was obtained from insurers who legally own the reports. A saturated sample of convenience of 184 cases with depression and pain as predominant symptoms were analysed. Recall bias were minimised through omission of personal identifiers and the use of a peer check of 20 random cases. Results in the peer check were suggestive of poor inter-rater reliability, rather than recall bias. METHOD: Cases were analysed according to the guidelines from the respective authors of the CAT and adapted Slick criteria, however this was further defined to ensure that the study could be replicated. RESULTS: Face validity was adequate in terms of purpose, item selection and association between consistency criteria, however require improvement in terms of standardised instruction and weighting of the scale. Content validity was rated as adequate to excellent, given that it supports criteria linked to the malingering construct. Construct validity was adequate as demonstrated by association between concepts obtained through concept analysis. Correlation between the CAT and adapted Slick was strong (r>0.5) however caution is expressed that this requires further research. CONCLUSION: Recommendations for further research included the review of content validity with subject experts, criterion and predictive valid through a case-control study of known-groups, as well as the reliability of the CAT, and the use of specialised ADL indices for malingering detection. Adaptation to the CAT was depicted in the proposed Consistency Assessment Tool.

AFRIKAANSE OPSOMMING: Malingering, die opsetlike nabootsing of oordrywing van simptome vir sekondêre gewin, het ‘n beduidende finansiële impak op ongeskiktheidsversekering as gevolg van die prevalensie daarvan. Multidissiplinêre professionele persone betrokke by ongeskiktheidsevaluasies het daarom ‘n meetinstrument nodig om moontlike malingeerders te identifiseer. DOEL: Die Credibility Assessment Tool (CAT), wat ontwikkel was as deel van die Performance APGAR, was ondersoek in terme van geldigheid en toepassing op malingering. Navorsingsdoelwitte het die ondersoek van voorkoms- en inhoudsgeldigheid deur ‘n literatuurstudie en konsep analise behels, sowel as konstruk- en korrelasie geldigheid deur die vergelyking van die resultate met beskikbare malingering protokolle en operasionele konstrukte. Die aangepaste Slick kriteria soos voorgestel deur Aronoff, wat toepaslik is op kroniese pyn, neurokognitiewe, neurologiese en psigiatriese simptome, was ge-identifiseer as die meeste gepaste kriterium standaard vir vergelyking. ONTWERP: Die studieontwerp was ‘n beskrywende analitiese studie wat retrospektief uitgevoer was deur ‘n ondersoek van verslae van versekeraars. Ingeligte toestemming was verkry van versekeraars wat die wetlike eienaars van die verslae is. ‘n Gerieflikheidsteekproef van 184 gevalle met depressie en pyn as hoof simptome was geanaliseer. Sydighede was verminder deur persoonlike inligting te verwyder en die gebruik van ‘n eweknie evaluasie van 20 ewekansige getrekte gevalle. Voorlopige resultate dui onbevredigende betroubaarheid aan, eerder as sydighede. METODE: Gevalle was ge-evalueer volgends die riglyne van die verskeie outeure van die CAT en aangepaste Slick kriteria, en was sodanig verder gedefinieer om te verseker dat die studie herhaal kan word. RESULTATE: Voorkomsgeldigheid was voldoende, maar verbetering is aanbeveel in terme van gestandardiseerde instruksie en skaal verdeling. Inhoudsgeldigheid was beduidend in vergelyking met die wetenskaplike literatuur en die geoperasionaliseerde konstrukte. Konstrukgeldigheid was bevestig deur die positiewe verhoudings tussen die aangepaste Slick en CAT kriteria. ‘n Sterk korrelasie was gevind tussen die aangepaste Slick en CAT, maar hierdie moet versigtig geinterpreteer word aangesien verdere navorsing verlang word. GEVOLGTREKKING: Aanbevelings vir verdere navorsing sluit in die ondersoek van die inhoudsgeldigheid met eksperte, kriterium- en voorspellingsgeldigheid, sowel as die betroubaarheid van die CAT en die gebruik van gespesialiseerde ADL indekse vir uitkenning van malingering. Aanpassing vir die CAT word ook voorgestel.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/6516
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