Incorrect encoding responses improve the classification accuracy of the Word Choice Test.

Area of Science:

• Neuropsychology
• Cognitive Assessment

Background:

• Performance validity testing (PVT) is crucial in neuropsychological evaluations.
• Traditional PVTs like the Word Choice Test (WCT) Summary score are widely used.
• Identifying novel indicators of performance validity can improve assessment accuracy.

Purpose of the Study:

• To investigate the utility of the WCT encoding trial responses as a supplemental performance validity indicator.
• To determine if combining the WCT Encoding score with the WCT Summary score enhances classification accuracy.
• To evaluate the impact of this combined approach on sensitivity and specificity.

Main Methods:

• 196 adult outpatients undergoing neuropsychological evaluations were studied.
• Participants were classified into valid and invalid performance groups using established PVTs.
• A novel "Encoding" score was derived from the WCT initial trial, using critical item analysis.
• Classification accuracy was assessed using receiver operating characteristic (ROC) analysis.

Main Results:

• The WCT Encoding score, with a cutoff of ≤40, showed potential as a validity indicator.
• Combining the Encoding score (≤40) and Summary score (≤42) significantly enhanced classification accuracy (AUC = .83).
• The combined approach increased sensitivity by .10 (to .58) while maintaining high specificity (.92).

Conclusions:

• The WCT Encoding score serves as a valuable supplemental index for performance validity.
• Integrating the Encoding and Summary scores optimizes the WCT without increasing evaluation time or cost.
• This combined strategy offers a more robust assessment of performance validity in clinical neuropsychology.