They measured absolute hyperactivity over each time interval. When the study was finished, it was unblinded, so only then did they know which children were treated with the test substance during which intervals. They then subtracted the scores while on placebo from the scores while on substance. In short: They measured the difference.
It does matter who judges; standard practice is to find the correlation of all experts on a sample, and verify it’s high, before the study begins.
They measured absolute hyperactivity over each time interval. When the study was finished, it was unblinded, so only then did they know which children were treated with the test substance during which intervals. They then subtracted the scores while on placebo from the scores while on substance. In short: They measured the difference.
It does matter who judges; standard practice is to find the correlation of all experts on a sample, and verify it’s high, before the study begins.