You need to distinguish between absolute observations (child is hyperactive) and relative observations (child was more hyperactive today than yesterday). The meta-analysis cited above uses relative observations. That’s why I wrote,
This isn’t saying that parents reported more hyperactivity than professionals. It’s saying that, across 15 double-blind placebo experiments, the behavior observed by parents had a strong correlation with whether the child received the test substance or the placebo, over four times as strong as that measured by professionals.
Very much agreed. One particular worry is that the substances in question are
dyes. If someone is observant enough to notice changes in visible color
in excretions, or skin color, the blinding is gone.
One another note, the topic of study
the link between food dyes and hyperactivity
almost begs for a bad joke about low-lying excited states...
No one has ever reported observing any such change from food dyes used in these dosages. These are comparable dosage levels to the amount of artificial coloring that most Americans eat every day.
Huh, I had meant that as a point in favor of the studies! Which I suppose it still is, but it hadn’t occurred to me that unblinding might occur in that way.
The fact that it’s 15 small studies rather than one large one actually works against it. Since the studies were conducted differently, the control is shaky.
You need to distinguish between absolute observations (child is hyperactive) and relative observations (child was more hyperactive today than yesterday). The meta-analysis cited above uses relative observations. That’s why I wrote,
Also, this was across 15 studies, not one study.
Also, blinding of the parents seems to be pretty key here.
Very much agreed. One particular worry is that the substances in question are dyes. If someone is observant enough to notice changes in visible color in excretions, or skin color, the blinding is gone.
One another note, the topic of study
almost begs for a bad joke about low-lying excited states...
No one has ever reported observing any such change from food dyes used in these dosages. These are comparable dosage levels to the amount of artificial coloring that most Americans eat every day.
Huh, I had meant that as a point in favor of the studies! Which I suppose it still is, but it hadn’t occurred to me that unblinding might occur in that way.
The fact that it’s 15 small studies rather than one large one actually works against it. Since the studies were conducted differently, the control is shaky.