Same name, (very) different persons, Ringer.
Schmidt (and also Jahn) made quite ingenious experiments on PK (psychokinesis). The details differed from experiment to experiment, but mostly their subjects sat in front of a display and 'willed' the lamps to go clockwise/counterclockwise.
They had novel features which made these experiments immune to several lines of critique applicable to older experiments:
- the randomiser was based on radioactive decay (that's where radioactivity came into it): such a randomiser is better than random number tables or randomiser used in cumputers for those are not truly random but only random for some tests of randomness
- the counting procedure was (as all of the experiment) computer controlled without any interference by humans: No (easy) bias in evaluation possible
- They ran clever control experiments like e.g. letting the apparatus run all night without a human trying to influence it before it: that excludes a 'drift' in the apparatus (nothing as bad as a subject 'willing' the lights to turn clockwise when the apparatus has a clockwise drift/bias) as explanation. For the same reason they had the subjects 'willing' a clockwise movement just as often as a counterclockwise.
Everybody I have read (or heard) believes the researchers to be completely honest. None of the usual counterexplanations that come easily to mind (bias in evaluation, trickery by subjects, wrong randomisation) holds here. Well, one of them could be true, in principle, but the researchers have taken all precautions against so it is not very probable.
There are some minor technical points that could hint to a normal explanation, but none of them has been convincing to me.
The main problem mainstream scientists have with the results is the tiny effect size. Jahn has reported a hit rate of 50.2 % (50.0 being chance) across experiments. That's highly significant with milions of trials, but it actually means that there is one extra clockwise movement among 500 trials.
For me personally, the most probable explanation here is some not yet detected error. For such a small extra-chance effect, even a very minor error suffices. It is not chance operating here, so much is sure. One camp, you may guess which, thinks the paranormal explanation is the only left, the other camp bets on a yet not detected minor flaw.