Ned misses an important point, that statistical models don't give you any idea what to measure. They simply tell you how to do what you are planning to do anyway in a way that might give statistically meaningful results. They do not have any underlying natural structure.
When I referred to doing the modelling first I was referring to models that actually describe the system and have some scientific basis. As an example of what I mean, I was once invited to develop a model of aquaculture impacts after several years of data had been collected. I began the workshop by asking about the nitrogen fluxes, since previous studies had shown that these were the most critical variables and would be a key element of any model. After a long pause I was informed that nitrogen had not been measured because no one thought it was important (actually, they didn't have the right equipment). If they had built a simple model first we might have had some useful data to work with. And of course I am not ruling out the possibility that the data might contradict the model. That is fine. That is how science develops. So I assure Ned that I am not talking about statistics, but science. Bill Silvert ----- Original Message ----- From: "Ned Dochtermann" <[EMAIL PROTECTED]> To: "'Bill Silvert'" <[EMAIL PROTECTED]>; <[email protected]> Sent: Thursday, March 09, 2006 4:23 PM Subject: RE: "Hamerstrom science" (deliberate non-use of statistical analysis) > Generally however those concerned, after the fact, about the rigor of > their > statistics (or lack thereof) are not reporting naturalistic observations > but > attempting to hammer their round data pegs into the square holes of > already > established theory. > > If your concern is naturalistic observation, you don't have to have too > much > concern about whether or not you've properly articulated (or understand) > the > underlying statistical model you're testing. > > Ned Dochtermann
