Reply #64: Sorry I'm not entirely engaging your point

[Time for change]

This post is in response to both you and Febble, since I believe that there is a lot of overlap.

The reason that I'm not entirely engaging your point is that I don't entirely understand your point. I can't read your post without having it seem to me that your main problem is with perceived small sample size -- or if there is another problem I don't understand what you're saying. Sure, in the example you give there is a 20% chance of obtaining the outlying result that you posit. But when the sample size becomes much bigger then, as you know, that problem goes away.

Febble also adds that sample size is a major problem with my idea. I don't understand that, since I'm talking about the means for 20 precincts.

Having said that, I need also to admit that the calculations that I noted in my previous post were off. Instead of a Kerry sampling rate of 87%, that should be 76%. But that assumes only an 80% Bush voter percent for the group, which is very conservative for the 80-100 category. Making a more reasonable assumption of 85%, the Kerry sampling rate rises to 82.7%.

So let me clarify:
For the 20 precincts in the Bush strongholds with the most negative WPE, assuming a Bush vote count of 85% for the group and a mean WPE of -14.2, we get a Kerry sampling rate of 82.7% and a Bush sampling rate of 51.3%. It is also important to mention that this differential sampling rate is the absolute minimum, because it assumes a mean WPE of -14.2, whereas that is the very least negative WPE that is possible from Mitofsky's data. The real WPE is certainly more negative than that, and possibly quite a bit more negative. I don't think that is plausible. If you do think it's plausible, is that because you think the numbers are small enough that sampling error could be a problem, or is there some other reason? Maybe you've already explained it above, but I just don't get it.

Maybe it's because you consider the 20 precincts to represent "cherry picking" from the 40 available precincts. Well, perhaps it is, but still I think that the differential is quite striking.

So what happens if we look at all 40 precincts? Still (assuming 85% Bush vote share) we get 74.7% Kerry voter sampling rate, vs. 52.7% Bush sampling rate (yes, 3 significant figures is probably too much). No cherry picking there. Considering that this applied to all 40 Bush stronghold precincts as a group, I think that this figure is also quite striking, though I still consider the figure for the 20 precincts more striking, notwithstanding the fact that they are a smaller and a select group. Anyhow, I just don't get the argument that this result can be discounted because of small sample size. What do you think the sample size is, anyhow?

Regarding the issue of sampling vs. response rate, I can't point you to a post. I believe that Febble and I discussed it by pm. Sampling rate is a simpler concept, because it is simply the number of responses, divided by the total attempted sample (the number of responses plus the number of refusals plus the number of misses). "Response rate" is the number of responses divided by the number "approached", so it would avoid the misses. By this definition, the numbers that Mitofsky presents would be sampling rate, rather than response rate. So I just think it gets unnecessarily complicated when you start talking about response rate (though I'm pretty sure that the great majority of the time, when someone uses that term, they are really referring to sampling rate, by the above definition.)