Wednesday, December 16, 2009

AAIDD intellectual disability manual (11th edition): Intelligence component -1 SD below average? Part 2 in series

As promised, this is the second in my series of comments re: the intellectual component of the new AAIDD manual.  I urge readers, if they have not done so, to read my original post.  In the first post I outlined the reason for the series.  I also highlighted positive features of the AAIDD component (chapter 4) of the manual and acknowledged that no manual will be perfect. 

Reproduced below are the four major concerns I raised re: the IQ component of the AAIDD 2010 manual:  In this second post in the series, I will address #3, as it lays the foundation for # 1 and #2. 
  1. A failure to reflect state-of-the-art intelligence theory and assessment research.
  2. A misunderstanding and inaccurate description of the major intelligence theories.
  3. An apparent lack of scientific rigor in the section on the nature and definition of intelligence as evidenced by little in the way of substantive revision of the content (and minimal reference updating or “refreshing”) from the 2002 manual to the same section in the 2010 manual—resulting in the failure to incorporate significant advances and the emerging consensus regarding the nature of psychometrically-based intelligence theories, theories that have historically provided the foundation for technically sound intelligence batteries used in ID diagnosis and classification.
  4. The elimination of the 2002 section that reviewed commonly available intelligence test batteries. 
Below is a table I constructed to organize my comments re: point #3 above.  The first column lists all references in the comparable chapter (4) in the 2002 red manual, minus the section that reviewed commonly available intelligence scales (which is no longer included in the 2010 red manual--#4 above).  The second column is an accounting of the references in the comparable chapter (again chapter 4) in the new 2010 green manual.  References that are retained are designated by an "X."  New references in the 2010 manual are listed.  The third column categorizes the topic area (in Chapter 4, 2010) that each new reference addresses.  All references (across editions) that in any way address any aspect of the nature, definition, and theories of intelligence are designated in bold font.  I will use this comparative table to organize my comments below. [Click here if you want a PDF copy of the table -- I recognize that the version embedded in the blog post is fuzzy and hard to I would suggest downloading the PDF file for a more readable version]

  • The new 2010 green manual chapter on intellectual functioning (hereafter simply referred to as the green manual; the 2002 hereafter referred to as the red manual), includes 26 different references not in the red manual.  Of those with a post-red manual publication date (2002-2010), there are 11 (starting with Luckasson et al., 2002).  Of these more contemporary references, none of them address the nature and definition of intelligence, as reflected in literature that informs the development and use of instruments to measure intellectual functioning.  Two of these citations reference the 2002 manual (or a related manual resource), 6 address the Flynn Effect, one deals with cutoff scores, and two cover issues related to extreme scores.  Surely significant research has been published since 2002 that addresses the definition, theories, and nature of the construct of intelligence. 
  • Of the 26 new green manual references, only 5 (approx 19 %) are included in sections addressing the definition, theories, and nature of intelligence.  The most recent of these 5 new references are 12-13 years old.  All other so defined references span the years from 1970 to 1990.
Comment #1:  This simple date-based tally, although not telling the complete story (which will be discussed below) suggests a lack of integration of contemporary intelligence research in the green manual.  As an applied psychometrician with active interests in intelligence theories and test development, the green manual appears (on face value) to already be out-of-date regarding contemporary developments re: psychometric theories of intelligence--theories that have produced significant improvements in existing (Wechslers) and new intelligence batteries.

But what of the 6 bold references in the red manual with dates between 2000-2002?  Did they provide an adequate assessment of the state-of-the-art of intelligence theories and definitions in the red manual?  Lets take a peek.
  • Four of these 6 references (Beebe et al, 2000; Kihlstrom & Cantor, 2000; Greenspan et al., 2001, Greenspan, in press [eventually published in 2003]) address issues related to the construct of social intelligence (e.g., how to measure it, gullibility, social vulnerability, etc.).  These are important topics, but they are not addressing the construct of psychometric intelligence--rather, they are focusing primarily on Greenspan's important work regarding social intelligence, a construct currently more associated with the definition and nature of adaptive behavior (AB).
  • The Davidson & Downing (2000) reference is related to Gardner's theory of multiple intelligences (MI), a theory that the green manual correctly points out as never resulting in any psychometrically sound practical assessment instrument for MR/ID identification.
  • Finally, the Glutting et al. (2000) reference is a test-specific citation related to the Wide Range Intelligence Test (WRIT).

Comment #2:  The lack of inclusion of all but one of these references (Greenspan et al., 2001) in the green manual does not appear to be a significant loss of information re: the definition, theories and nature of intelligence.  However, what does this say about the most contemporary references in the preceding red manual?

Going back further in the red manual (first column), one does not locate solid psychometric intelligence theory and research references until 1997. On what evidence do I base this claim?
  • Two of the references (Chen & Gardner, 1997; Gardner, 1998) again deal with Gardner's theory of MI (see comment above).
  • Three are by Greenspan and colleagues and address important issues---but unfortunately not issues related to consensus-based theories of intelligence that have produced useful tools for MR/ID diagnosis and classification.  Greenspan & Love (1997) cover the construct of social intelligence; Greenspan (1997) was a critique of the earlier blue maual ("Dead Manual Walking"); Greenspan (199b) focused on the definition of mental retardation.
  • The three intelligence definition/theory references (in the red manual) which (IMHO) are representative of literature addressing contemporary general intelligence research and theory (with implications for assessment and identification of MR/ID) are Carroll (1997b), Gottfredson (1997) and Naglieri (1997). Of these three, two (Gottfredson, 1997; Naglieri & Das, 1997) are still in the green manual.  
Comment #3:  The preceding analysis, when combined with Comment #1, suggests that the current 2010 AAIDD green manuals scientific and research foundation for the first prong of MR/ID diagnosis and classification (intellectual functioning) is based primarily on literature that is out of date....12-13 years old (1996-1997). 

Comment # 4:  Although the green book did not include a section on commonly used intelligence tests, a number of references citing select cognitive measures are similarly dated.  The chapter repeatedly refers to the 1986 SB4.  The SB4 was revised to the SB5 in 2003.  When mentioning special purpose tests, reference is made to the original CTONI (1997) and not the recently revised CTONI-2 (2009) and the 1983 Slossen Intelligence Test which has also been revised (most current publication date is 2002).

Concluding comment:  An analysis of the reference literature cited in of the AAIDD 2010 green manual's definition of intelligence chapter (which is critically related to the diagnosis and identification of individuals with ID) is dated (over 10 years old).  Significant consensus-based developments have occurred during this period of time and, unfortunately, the AAIDD manual fails to ground it's definition of intelligence in contemporary intelligence research

In my next series of posts, which will be the most important in the series, I will defend my conclusions via the provision of references and empirically-based conclusions that have been emerged from the field of intelligence research, theory and test development.  Regular readers of this blog (and those familiar with my research) obviously know where I am headed.  Individuals who want to develop an "advanced organizer" for this forthcoming material should consider consulting information provided here, here, here, here, here, and here.  For those who are very ambitious, I've generated a rather lengthy reference list that demonstrates the breadth and depth of contemporary psychometric research that has recently converged on a general consensus re: the nature and structure of psychometric intelligence.  More importantly, this extant research has resulted in a wealth of available contemporary IQ batteries that can be used in the idenification of individuals with ID.  I will be summarizing this information in my next posts in this series---so, sit back if you do not have time and want the Readers Digest version.  It may be a week or so before I can develop this more content-heavy material.

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