Rich Ulrich wrote:
> These are not quite equivalent options since the first one really
> stinks -- If you are considering drawing conclusions about causation,
> you need *random assignment* and the two Groups of performance are the
> furthest thing from random.
>
> Let's see: the simple notion of regression-to-the-mean says that the
> Best performers should fall back, the Worst performers should improve;
> that's a weird main-effect, which should wreak havoc with interpreting
> other effects.
> Or: If the Pre is powerful enough to measure potential, then a
> continued-growth model says that Best performers should improve more,
> even given no treatments.
This pattern was described in an obit about two-three years ago in the
NY Times. A statistician's obit noted that he'd found a flaw in the
Israeli air force's training program. Apparently, the Israeli air force
was punishing the worst performers in a test because this usually
produced a better performance in subsequent tests and was supposedly
much more effective than positive reinforcement. They'd found that
positive reinforcement of the best performers often resulted in a poorer
performance on the next test. This now-deceased statistician pointed
out the confounding effect of regression to the mean on this assessement
of negative and positive reinforcement. The effectiveness of negative
reinforcement (punishment) could be nothing more than a chance effect.
I wish I had the citation for the study or the obit.
Does anyone else in the group have a citation of this study?
--
Eugene D. Gallagher
ECOS, UMASS/Boston
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