From the foreword to the WMT Test Manual
by Dr. Paul Lees-Haley
In the plethora of methods for identifying invalid test data, Dr. Paul Green’s Word Memory Test (WMT) stands out as the most thoroughly researched and intensively cross-validated of them all. With his focus on measuring effort, Dr. Green has effectively concentrated on the behavior of the examinee most relevant to the validity of neuropsychological assessment. This was a critical decision because it permits the user of the WMT to assess the primary issue – validity of the results – without becoming ensnared in the thicket of differentiating various response biases, malingering, confusion between subjective reporting and objective testing, and the worrisome issue of conscious intent. Using extensive data from relevant comparison groups, Dr. Green measures effort empirically rather than based on subjective impressions of experts or self-reports of examinees.
Most research on assessment of invalid psychological and neuropsychological test results has used data produced by simulators (usually college students) rather than known groups. Dr. Green, along with colleagues including Dr. Roger Gervais and Dr. Lloyd Flaro, has collected comparison data from numerous groups ranging from compensation-seeking claimants to neurological patients with brain tumors, strokes, ruptured aneurysms, et cetera, depressed adults, both mild and severe traumatically brain injured adults, children with fetal alcohol syndrome, children with neurological diseases, and others.
The importance of the effort assessment research led by Dr. Paul Green cannot be overstated. Recent findings on the amount of variance accounted for by effort raise questions about the validity of a host of neuropsychological and psychological research studies dating back to the origins of cognitive assessment. A random perusal of empirical studies in neuropsychological and psychological journals reveals a pervasive tendency to presume that diagnoses and test results are valid based on various methods of clinical assessment with no correction for effort based on any empirical method.
Although blatantly uncooperative participants are typically excluded, empirically measured effort has not been used as an exclusion factor in literally thousands of studies in which effort is essential to the validity of the results. This omission is present in normative studies and validation studies of widely used tests as well as most other studies employing neuropsychological or neurobehavioral tests. The implication is that a cross validation of prior research using effort as an exclusion criterion may lead to significantly different conclusions in many studies presently relied upon by experts in the field. Neuropsychological assessments are no longer complete without evaluation of effort.
Paul R. Lees-Haley, Ph.D., ABPP
September 6, 2003
Ethics & SVTs by Iverson