I'm grateful to Harold Doherty for providing me with a distraction from being pulverized at the Tribunal. Mr Doherty is doing science again, with the usual autism advocacy standards. This time, Mr Doherty takes on a "myth" about the intake IQs of the experimental group in Lovaas (1987).
So let's look at those intake IQs.
I'm not going to launch into a lecture about deviation vs ratio IQs. This is a relevant issue here, but it can largely be circumvented by using the measure Lovaas (1987) used at intake, the PMA (prorated mental age), and its derived ratio IQs. All the sources I cite are peer-reviewed journal articles with Ivar Lovaas in the authorship, and the information I provide can be verified from these articles.
Using the reported PMA in Lovaas (1987), the mean intake IQ in the experimental group is 63. This is an average score in the "mildly retarded" range.
In the "Method" section, Lovaas (1987) also reports that, at intake, 2 experimental group children were in the normal range of intelligence (IQ 70 or more); none was in the "mildly retarded" range (IQ 50-69); 7 were in the "moderately retarded" range (IQ 35-49); and 10 were in the "severely retarded" range (IQ 20-34). None was in the "profoundly retarded" range (IQ of less than 20). Dr Lovaas also reports that this distribution of IQ scores is "identical to that for Control Group 1".
But--even if you assign the normal range children an IQ of 100--I haven't been able to find any report of the range of ratio IQs for the whole experimental group--and also assign all the other children to the highest possible scores in their respective categories (7 children with 49 IQ; 10 children with 34 IQ), this does not even approach a group average of 63. Instead, the average is 46.
It is statistically improbable that all those kids had, at intake, the highest scores within their assigned ranges, and it also looks impossible for the two normal range children to have ratio IQs as high as 100 (this would be inconsistent with reported deviation IQs; McEachin et al., 1993). But even this exercise in trying to produce the highest possible average intake IQ falls well short (17 points) of the reported average.
In the "Results" section, Lovaas (1987) reports that at intake, there were 10 children in the "moderate to severe range", as opposed to the 17 ("moderate" plus "severe" children) reported earlier in this paper.
Smith et al. (1993) report that 5 of the 19 children in Control Group 1 in Lovaas (1987) were "high-functioning", that is, had an IQ of 70 or more at intake. This contradicts the account in Lovaas (1987), where it is reported that only 2 of the 19 children in both the experimental group and Control Group 1 had IQs in the normal range (70 or more). Smith and Lovaas (1997) report a total of 9 children (experimental group and Control Group 1) who have IQs of 75 or more. If this figure is correct, and if 5 of these children were indeed in Control Group 1 (assuming none of the kids with IQs over 70 had IQs under 75...), then 4 must have been in the experimental group. This leaves open the question of whether the experimental group might have included more than 4 children with IQs of 70 or more.
Smith et al. (1997) correctly report that all children with ratio IQs of less than 37 were excluded from Lovaas (1987). That is, none of the experimental group children in Lovaas (1987) was in the "severely retarded" range at intake. This is contrary to what is stated in Lovaas (1987), where it is reported that 10 children--the majority--are in this range.
Lovaas and Smith (1988) add that the average intake IQ of the 9 children who achieved "normal functioning" in Lovaas (1987) is "slightly under 70". In fact it is 70 (69.7), which would be considered (just) in the normal range. And "in the normal range" is another way to say "high-functioning".
Summary?
Lovaas (1987) does not include any autistic children whose intake IQs are in the "severe" and "profound" ranges. The average experimental group intake IQ is in the "mild" range, and the average for those children who achieved normal functioning is (just) in the normal--"high functioning"--range. And the distribution of intake IQ scores is incorrectly (and inconsistently) reported in Lovaas (1987).
These are data I absorbed long ago and carried around for a long time. Only when I saw Mr Doherty's latest foray into science was I reminded to cough them up. Autism advocates who use websites as authoritative sources miss all the fun (and avoid all the hard work) of looking at data from primary sources. As usual, any factual criticisms are welcome--and if anyone can find (I'm sure it's right in front of me somewhere...) a reported range of ratio IQs (not deviation IQs) for the full experimental group in Lovaas (1987), you'll be awarded a trip to that Tribunal hearing (or maybe not).
References:
Lovaas, O.I. (1987). Behavioral treatment and normal educational and intellectual functioning in young autistic children. Journal of Consulting and Clinical Psychology, 55, 3-9.
Lovaas, O.I., and Smith, T. (1988). Intensive behavioral treatment for young autistic children. In B.B. Lahey, and A.E. Kazdin (Eds.), Advances in Clinical Child Psychology, 11. New York: Plenum Press.
McEachin, J.J., Smith, T., and Lovaas, O.I. (1993). Long-term outcome for children with autism who received early intensive behavioral treatment. American Journal on Mental Retardation, 97, 359-72.
Smith, T., & Lovaas, O.I. (1997). The UCLA Young Autism Project: A reply to Gresham and McMillan. Behavioral Disorders, 22, 202– 218.
Smith, T., McEachin, J.J., & Lovaas, O.I. (1993). Comments on replication and evaluation of outcome. American Journal on Mental Retardation, 97, 385–391.
Smith, T., Eikeseth, S., Klevstrand, M., and Lovaas, O.I. (1997). Intensive behavioral treatment for preschoolers with severe mental retardation and pervasive developmental disorder. American Journal on Mental Retardation 103, 238-249.
