Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!henry From: henry@utzoo.UUCP (Henry Spencer) Newsgroups: net.misc Subject: psi-missing Message-ID: <3114@utzoo.UUCP> Date: Fri, 22-Jul-83 17:40:55 EDT Article-I.D.: utzoo.3114 Posted: Fri Jul 22 17:40:55 1983 Date-Received: Fri, 22-Jul-83 17:40:55 EDT References: gatech.307, <5589@unc.UUCP> Organization: U of Toronto Zoology Lines: 30 The problem with invoking the "psi-missing" phenomenon is that it is just one of many ways to explain away a failed experiment. It is true that if the score on your experiment is significantly worse than chance, this is significant data. However, it is *still* a negative result on *that* experiment. If any conceivable experimental result can be explained away in a manner that doesn't conflict with the original hypo- thesis, then what you are doing is not really an experiment at all. The history of psi experimenting is rife with incidents of experiments with superficially-negative results being explained away by looking for some correlation, *any* correlation, in the data. If you look long enough and hard enough, you will most assuredly find *something* that looks non-random in any finite set of data. There is a simple and well-known method of guarding against such unscientific fudging, while nevertheless allowing for the difficulties of not knowing exactly what you are looking for. Once you have run your experimental trials, you split your data into two halves along a dividing line that was fixed in advance. The second half of the data is put to one side; you don't look at it just yet. You then analyze the first half in any way you please, looking for any sort of correlation. Having done this analysis and decided what sort of correlation you are getting, you write down an exact statement of the resulting hypothesis. Then you check to see if the second half of the data confirms it. If it doesn't, your results are negative, period -- no further shuffling of hypotheses or rearranging of the calculations is allowed. The more careful psi experimenters use this sort of method routinely, and their results to date are 100% negative. -- Henry Spencer @ U of Toronto Zoology {allegra,ihnp4,linus,decvax}!utzoo!henry