Monday, September 03, 2007

WISC-III/IV scatter/FS IQ study - Hale responds to Lopez

Yesterday's guest blog post by Ruben Lopez generated a lengthy response by Dr. James "Brad" Hale, a regular voice on the NASP and CHC listservs on this particular topic (interpretation of composite and test scores on intelligence tests). To those who are not members of either of these lists, Brad has regularly challenged the statistical arguments/methods behind the research illustrated by the Watkins et al. article Ruben reviewed. In fact, in the same issue of Applied Neuropsychology, Hale et al outline their arguments (click here to view/download). [Note - see previous post on this blog about this entire special issue. There are a number of positions and arguments surrounding this entire topic..Brad's position is not the only position]

In an attempt to provide some balance, I decided to lift Brad's response from the NASP listserv and post it here at IQ's Corner. This will allow others to become aware of Brad's arguments and should help save bandwith on these two lists---as Brad (and others) can then simply refer people to this more permanent post at IQ's Corner for Brad's arguments and thoughts [Note to Brad - maybe this post can save you from having to repeatedly articulate your thoughts and ideas on the listservs...just insert a URL link to this post.]. Also, in the past other voices have been heard in response to Brad's arguments, challenges and claims. I would encourage any of those voices to contact me if they want to provide a counter-response (

Please note that my posting of Brad's response does not mean I endorse his arguments or claims. They are presented "as is." As blogmaster I would LOVE it if authors of the other articles in the special AN issue would respond with written responses I could post in the form of blog posts.
  • I mean no offense to Ruben Lopez, as he seems well-intentioned, but this is clear evidence of why the Watkins et al. results are so problematic, and could be seen as unethical. Why? Because practitioners such as Mr. Lopez read the positions and analyses of these authors, and conclude they "appear reasonable" (quote from Mr. Lopez). Then Mr. Lopez goes on to conclude "So, I won't disregard the full scale solely because of scatter". If the analyses are wrong as I suggest, this is clear evidence that at least one practitioner (and likely others) has been misinformed by this study, and this affects his (their?) practice of psychology.
  • This is very sad because in the rebuttal paper of this very same special issue (Hale et al., 2007), statistical analyses are provided that clearly show the errors in the Watkin's paper. Yes, errors. Those are strong words folks, yep. I wouldn't say they were errors unless I was convinced the data shows they are errors. It is all there in black and white folks. It isn't a matter of opinion, rather one of fact, and I challenge any statistician to go on record to say that the Watkins analysis is right, and our rebuttal analyses are wrong. *Please*, statisticians only! These are complex statistical arguments and it would be best if statisticians determine who is correct. Whether you believe in the value of global IQ or not, that is not the issue. The issue has solely to do with statistical analyses.
  • Again, please have any statistician who is willing to come forth and show/argue we are wrong, please do so. Please have them provide their full name and other identifying information so they may be contacted at a later date.
  • As for why people would continue to value and/or support papers that have significant statistical errors, or even be willing to publish them- that is up to the reader to determine. I won't even speculate because that could be seen as an ad hominem attack. I do find it interesting that someone could read one article in the special issue and say it is good, but not mention the other articles, which show it is not!
  • If I am right, and these analyses are statistically inappropriate, and they are used to inform practitioners about clinical practice (as are many of the other papers produced by this academic group - which we also show in the rebuttal paper), there is a serious ethical problem here. I have personally contacted the authors and directly informed them of the statistical errors in other papers, and I have also contacted editors.
  • We have also shown why the analyses are wrong in several published works. Yet, the works by this academic group continue to be endorsed by others, even those with the statistical sophistication to know better. It is a sad day in science when people's opinions and values superseed the facts. I guess we have to ask ourselves as a profession a very important question. Are we guided by scientific fact or fancy? It is up for all of us to decide.
  • Please do forward this email to anyone you think is willing to reply, including Drs.Watkins and Glutting.

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