Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site amdahl.UUCP Path: utzoo!decvax!decwrl!sun!amdahl!ems From: ems@amdahl.UUCP (ems) Newsgroups: net.med Subject: Re: Placebos CANNOT cause cancer!!! Message-ID: <1592@amdahl.UUCP> Date: Fri, 31-May-85 15:58:07 EDT Article-I.D.: amdahl.1592 Posted: Fri May 31 15:58:07 1985 Date-Received: Sat, 1-Jun-85 04:42:30 EDT References: <1589@aecom.UUCP> <1273@hammer.UUCP> <1550@amdahl.UUCP> <1685@aecom.UUCP> Distribution: na Organization: Circle C Shellfish Ranch, Shores-of-the-Pacific, Ca Lines: 102 > Before any more of this nonsense gets posted: Excuse me, but I was not notified when you were appointed censor-of-net-med. Might I see the official document that empowers you to pass judgement on others? > First seifert@mako didn't get the statistics. Now ems@amdahl is > blaming everything on miniscule amounts of dye. First, as I remember it, the question was asked (paraphrase) - or is the sample size too small ... - This would indicate to me an understanding of the basic statistics, but a disire to avoid digging out the stats book to calculate the sample size needed for a small standard deviation when other important factors were not available to the person asking. It did not show, to me, that mako "didn't get" the statistics, but rather that they understood the statistics and were asking for an estimate of standard deviation for that sample size. Second, I don't remember 'blaming everything' on dye. I do remember *ASKING* if you could state with certainty that the dye was not implicated, along with other potentially overlooked items. I do believe that *MOST LIKELY* the effect was a statistical anomaly; however, I also appreciate that we cannot really *KNOW* that it was. That was my point. We can make reasoned guesses based on the best double blind studies using the tools of statistics, but we cannot truely *KNOW*. Using Occam's Razor, we will choose one *THEORY* to beleive in as true, until it is superceeded by another. When an anomaly such as this happens, the proper course is to look for an independent variable that was thought to be a constant. Rember Legionairs Disease? Statistic or an unknown effect? It may be the dye, the office that the placebo was given in (If different from where the test drug was given - there are cases of radiation leaking through walls ...), a lack of 100% purity in the starch preparation, etc. If none is found it does not prove randomness, it proves either randomness *OR* that we have not found the cause. We then assume for convenience that it was randomness, pending further data. As for the amount of dye being small: What dose level of dioxin is needed to induce cell changes? Carcinogens are often noted for the very low levels needed to cause problems. What organic chemical reaction produces 100% (integer, not rounded float) pure product? (Please consult your organic chem texts, stats books, and physics texts - isotopes you know - before answering) My point remains: you can not know. You can assume. > OK, this is getting ridiculous. Yes, it was. > If the packaging caused cancer, then > you would expect people in the experimental group to get cancer, too., Only if the packaging were identical. You have not stated that this is so. While it is inferred, it is not a given. > Also, > how much difference will one pill make in total chemical intake (it was one > pill/day) That depends on what is in the pill. All chemicals are not created equal. > Two, chemical carcinogens tend to be organ specific - in this study > 5 patients got five different cancers -- all of them common in the population. A good point. This was missing from your earlier posting and is valuable information. But please notice the phrase 'tend to be'. We are agreeing here that they need not be. You are assuming that there is not a chemical carcinogen because of a trend, not a 100% rule. This still leaves room for uncertainty. > We CAN be sure. They didn't get the cancer by increasing their total dye > intake by .0001% of daily intake. Depends on the dye and any contamination. Were the placebos prepared in the same place and at the same time as the drugs? Were *ALL* of the factors held constant? Was there *NO* chance for contamination at *ANY* step? It has often been true that the perplexing 'statistical' anomalies overlooked by one researcher were the seed of brilliant discoveries when investigated by another. > DO NOT, I PLEAD, DO NOT, respond to this article with a POSTING!!! Why not? You have raised some issues that need responding too. Is there a reason not to do it in the same public forum where they were raised? Please forgive my usual compliment of spelling, diction, style, grammar, etc. errors. -- E. Michael Smith ...!{hplabs,ihnp4,amd,nsc}!amdahl!ems Tilapia Zilli is the way and the light. This is the obligatory disclaimer of everything.