• G J Meyer.
• Department of Psychology, University of Alaska Anchorage, USA. afgjm@uaa.alaska.edu
• J Pers Assess. 2000 Aug 1; 75 (1): 46-81.

AbstractWood et al.'s (1999b) article contained several general points that are quite sound. Conducting research with an extreme groups design does produce effect sizes that are larger than those observed in an unselected population. Appropriate control groups are important for any study that wishes to shed light on the characteristics of a targeted experimental group and experimental validity is enhanced when researchers collect data from both groups simultaneously. Diagnostic efficiency statistics--or any summary measures of test validity--should be trusted more when they are drawn from multiple studies conducted by different investigators across numerous settings rather than from a single investigator's work. There should be no question that these points are correct. However, I have pointed out numerous problems with specific aspects of Wood et al.'s (1999b) article. Wood et al. gave improper citations that claimed researchers found or said things that they did not. Wood et al. indicated my data set did not support the incremental validity of the Rorschach over the MMPI-2 when, in fact, my study never reported such an analysis and my data actually reveal that the opposite conclusion is warranted. Wood et al. asserted there was only one proper way to conduct incremental validity analyses even though experts have described how their recommended procedure can lead to significant complications. Wood et al. cited a section of Cohen and Cohen (1983) to bolster their claim that hierarchical and step-wise regression procedures were incompatible and to criticize Burns and Viglione's (1996) regression analysis. However, that section of Cohen and Cohen's text actually contradicted Wood et al.'s argument. Wood et al. tried to convince readers that Burns and Viglione used improper alpha levels and drew improper conclusions from their regression data although Burns and Viglione had followed the research evidence on this topic and the expert recommendations provided in Hosmer and Lemeshow's (1989) classic text. Wood et al. oversimplified issues associated with extreme group research designs and erroneously suggested that diagnostic studies were immune from interpretive confounds that can be associated with this type of design. Wood et al. ignored or dismissed the valid reasons why Burns and Viglione used an extreme groups design, and they never mentioned how Burns and Viglione used a homogeneous sample that actually was likely to find smaller than normal effect sizes. Wood et al. also overlooked the fact that Burns and Viglione identified their results as applying to female nonpatients; they never suggested their findings would characterize those obtained from a clinical sample. Wood et al. criticized composite measures although some of the most important and classic findings in the history of research on personality recommend composite measures as a way to minimize error and maximize validity. Wood et al. also were mistaken about the elements that constitute an optimal composite measure. Wood et al. apparently ignored the factor-analytic evidence that demonstrated how Burns and Viglione created a reasonable composite scale, and Wood et al. similarly ignored the clear evidence that supported the content and criterion related validity of the EMRF. With respect to the HEV, Wood et al. created a z-score formula that used the wrong means and standard deviations. They continued to use this formula despite being informed that it was incorrect. Subsequently, Wood et al. told readers that their faulty z-score formula was "incompatible" with the proper weighted formula and asserted that the two formulas "do not yield identical results" and "do not yield HEV scores that are identical or even very close." These published claims were made even though Wood et al. had seen the results from eight large samples, all of which demonstrated that their wrong formula had correlations greater than .998 with the correct formula. At worst, it seems that Wood et al. (199

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