--- In [email protected], akasha_108 <[EMAIL PROTECTED]> wrote: > > --- In [email protected], "authfriend" <[EMAIL PROTECTED]> wrote: > > > > --- In [email protected], "markmeredith2002" > > <[EMAIL PROTECTED]> wrote: > > > > > > > > > If the DC crime rate was > > > > > > relatively flat during the 90s, maybe that's an ok > > methodology. But > > > > > > metro cities throughout the nation experienced a dramatic > > drop in > > > > > > crime rate starting around 1992-1993 and continuing for > > several yrs > > > > > > and therefore the study can't prove its point w/o controlling > > for > > > > > > this major factor. > > > > > > > > > > They did, by "predicting" what the crime rate *would* have > > > > > been for that period that year on the basis of the previous > > > > > five-year trend. It's true that there might have been > > > > > *somewhat* less of a reduction if the crime rate had started > > > > > going down in early 1993, but you would have no reason to > > > > > see the sharp, sudden drop they measured during the project > > > > > on the basis of the decline you're talking about (much less > > > > > the return to "normal" a few weeks after the study). > > > > > > The 5 yr trend is meaningless - the trend for violent crime was > > > significantly up during the 80s and then it unexpectedly and > > > dramatically turned down in the 90s, then flattened out near the end > > > of that decade. All sorts of studies came out in the 90s supposedly > > > proving that this or that particular program was reducing crime in > > > this or that city, but in retrospect we now know that crime was > > > going down in all large cities, even ones not doing this or that. > > > > Wow. You're still not getting it, and I'm not sure > > how to clear it up for you. Maybe you could just try > > reading what I wrote above a little more carefully. > > Everything you just said is utterly irrelevant in the > > case of this study. > > I think Mark's point is, similar to mine a month ago on this topic, if > a model to estimate (weather and other factor) normalized crime rates > for the intervention period were developed, it would have to be a > multi-year model at least five years or so -- longer would be much > better.
That doesn't appear to be what he's talking about at all. But it *was* five years (check the URL I gave in a previous post). <snip> > > If the crime rate were trending down over those five > > years, or just the last two of those years, it would > > be reflected in the "prediction" of what the crime > > rate *would have been* if the project hadn't been > > conducted during those eight weeks. > > I know you (probably) don't see it because you have never done this > type of analysis (I assume), but what you just said suggests two > models: a long term model to estimate (not predict that references > the future) a weather normalized crime rate and a short term impact > model. > > Normally this would NOT be a separate step and NOT two models. A > single well constructed model would control for weather, > sociological and crime-factor variabes, and the intervention > variable, ALL AT THE SAME TIME. Apparently, for reasons not clear, > they did not do this. I don't see how you possibly *could* do it. Now I'm not sure that you have *any* idea of how the study was done, and I'm helpless because I don't know where your misunderstanding lies. <snip> > > > I'm saying the study design needs to be revisited due to what we > now know about the unique crime trends in the 90s. > > > > Nope, not for an eight-week World Peace Assembly. > > How are you going to control for weather effects then? You need a > longer term model to do that. As well as for other crime factors. Again, the crime trends, whatever they were, would be automatically reflected in the analysis that estimated the crime rate for the eight-week period without the intervention. > > Now, *that's* entirely reasonable. (The data itself is > > public; > > Is it. How can I acess it? FBI crime stats. ------------------------ Yahoo! Groups Sponsor --------------------~--> Get fast access to your favorite Yahoo! Groups. Make Yahoo! your home page http://us.click.yahoo.com/dpRU5A/wUILAA/yQLSAA/JjtolB/TM --------------------------------------------------------------------~-> To subscribe, send a message to: [EMAIL PROTECTED] Or go to: http://groups.yahoo.com/group/FairfieldLife/ and click 'Join This Group!' Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/FairfieldLife/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
