--- In [email protected], new.morning <[EMAIL PROTECTED]> wrote: > > --- In [email protected], "authfriend" <jstein@> wrote: <snip> > > Remember, what the guy is defending against is > > the accusation by the critic that the 36-hour spike > > in the murder rate meant the whole study was a > > complete failure. What he's doing is explaining > > why it didn't mean that at all. > > > > On the other hand, the numbers involved wouldn't be > > enough to significantly affect the results even if > > the murder spike *had* been included. > > But, IMO, each crime type should have been analyzed separated.
Yes, I understand your objection on those grounds. But it doesn't address my point about the way the study *was* done. <snip> > And the impact, other than in 1-2 weeks, looks pretty modest. And > the fact that there was a big drop in cime in 1-2 weeeks and not > others is unexplained Wasn't their explanation that this was when the largest number were participating? I thought that was mentioned in the rebuttal. > -- and adds the premise of a highly fluctuating "sea" of > crime rates. Well, but murder was the *only* rate that fluctuated in a way inconsistent with the study hypothesis. <snip> > > What about the fact that there is normally such a > > small number of murders (only 3 percent of violent > > crime in 1993 as a whole)? Is it not the case that, > > as he says, "with numbers as low as this...random > > fluctuations can appear extremely high when listed > > as percentages"? > > His point is valid, but off the main point, IMO. If you average 10 > murders a week, and you get 20 in a particualr week, its not an > aberation to say murders doubled in that week. No, and he certainly doesn't deny that murders doubled in that week (the additional ones coming in a 36-hour period). All he was doing in the part of the rebuttal I quoted was pointing out why that spike didn't invalidate the rest of the study. > Where his point would have relevance is in murders in a small town > like FF. If there is one every five years, and you get one this > year, the percentage increase for the year is 500% (if you used the > average of 1/5th). Or god forbid, two in one year: 1000% That is a > distorted view, IMO. I don't see why the point doesn't also have relevance for the murder spike in the D.C. study, if to a less extreme degree. > > In any case, I'm not sure in what way your second > > objection relates to the point he was trying to > > make, i.e., that the spike doesn't affect the > > study's conclusions. > > I was commenting on the 3-4 paragraphs you provided, and asked for > comment on, not just that one point. If I got "off point", sorry. > But I don't see where. That was the only point he was making in what I quoted! <snip> > > >By averaging, with assaults being by far the highest > > > category, the study becomes essentially a study on assaults. > > > Effects on murders and to a lesser degree, rapes, are > > > submerged. > > > > This makes sense to me as a criticism of the > > study design. Why they chose to lump all violent > > crime together isn't entirely clear, but I can't > > imagine they did this because they *expected* the > > murder rate to spike and *wanted* to submerge it. > > I am not sure pooling was part of the pre-study study design. There > can be a lot of leeway if reporting results. I suspect they pooled > results because it gave a clearer less ambigous picture. No, they were following the pre-study design as closely as they could; the protocol specified the total number of all violent crimes and said nothing about studying each type separately. Pooling was what they explicitly said they were going to do. I have a copy of the original protocol, but all my TM-related papers are in storage where I can't get at them easily. The fact that they drew up, in consultation with an independent review board, a protocol before the study commenced, and publicized it widely, was a big deal; this was designed specifically to address the kind of drawing-the-target-around the-arrow questions you're raising. > I don't think they felt bound by any pre-study articulation of thier > analysis plan. They very much *did* feel bound by it, actually. > And it would have been silly to state "we are not going > to look at each crime by itself." > > > I suspect they did it because it wouldn't sound as > > impressive, PR-wise, to claim a decline merely in > > assaults, as opposed to a decline in all violent > > crime; > > And that murders and/or rapes went up. Sure. But my point is, they *expected* them all to go down. <snip> > > Anyway, I'm *still* not clear why you think his > > explanation for why the spike didn't invalidate > > the study, as the critic claimed, lessens his > > credibility, > > I raised three points in the above post, and several more in a prior > post, that I thought were weak. Regardless of why they were being > raised. None of your points, as far as I can tell, addressed your stated distrust of his credibility specifically on the basis of his explanation for why the spike didn't invalidate the study. That's the only thing I was asking about, not flaws in the study design per se, although your ideas on those have been interesting.
