"How many hours is forty hours? Range of treatment intensity in Lovaas (1987)" was an IMFAR 2007 poster. You can find the abstract (which has an error, corrected in the poster itself) within the IMFAR 2007 program or on my blog.
This work remains unfinished. As with other important issues, I've failed to influence people better placed than I to take on the 40 hours figure. Meanwhile this figure has carried and continues to carry enormous consequences for autistics everywhere, in research, practice, policy, law, etc.
Full, accurate information about treatment intensity in Lovaas (1987) and its relation with outcomes remains unavailable in the literature. Instead, inaccurate claims remain dominant, we still don't know how many hours is 40 hours, and (almost) no one cares.
You can find a bit more about treatment intensity in ABA-based autism interventions, and how this is or isn't reported, elsewhere in my unfinished work: here
NOTE: The pdf of this poster makes it difficult to read the three excerpts from Leaf’s testimony (from Wynberg et al. v. Ontario, Leaf, pp. 16687-16692 [Compendium, Vol. II, Tab 23, pp. 692-697]), under the heading,
For this reason, the content of these three excerpts is provided below.
A. It was an average of 40 hours. There were children that received less than 20.
A. One child, I was the direct—I was the clinic—I was the senior therapist on that case, and when I was Clinical Supervisor he received 18 hours a week. There was another little girl that received approximately the same amount of hours. So there were two children during the time I was there that received less than 20 hours.
A. In the 1987 article was the basis of this, this now comes straight from ’87. So the ’87 article was very clear in that. Recently Dr Lovaas and I had a conversation where we went over every child’s hours just to make sure that we were on the same page and we’re in complete agreement on the range of hours that children receive. And the range we agreed was 18 hours to the upper hours being in the 50 range.
Q. All right. And then did both of the children who received under 20 receive 18 hours?
A. They received—well, it changed over time. They started with 18, it lessened over time. And both of those children were in the best outcome group.
Q. And that fact has not specifically been published in the literature as far as you’re aware?
A. No, it was not published in the literature. The range of hours was not published in the literature. Nor was it specific about which children—where they were in the range those that had the best outcome.