There are many arguments we can make to judge polls. That was my old job - trying to figure out what LV screens work best. You're right that after a certain point the differences become very subtle, although usually surmountable, but even if they weren't...
...this is still wrong. Accurate has a specific definition. A sample is accurate if the expected outcome is equal to the population. If one of the samples is more accurate than the others, then averaging it produces a new, less accurate sample. Suppose we don't have any reason to suppose that any of the samples is any more accurate than the other. This implies that we *also* don't have any reason to suppose that average would be any more accurate than the original samples. So there's *still* no reason to average.
My point here isn't that you'll be accurate, but that I find your level of accuracy appropriate for your argument if you average. If you just guess, then even if you're correct, (in my classes at least) I'd throw the whole answer out. If it isn't justifiable, then it's quite literally worthless. I admit this is probably not how political scientists view this though judging from your experience and your response. I come from a pure math background, so it's a feature of the field that unsubstantiated answers are entirely incorrect.
Instead, the best thing to do, in the absence of any other information, is just to provide all three separate results, with the different assumptions attached. That's it. You could provide the average too, but it doesn't give you any additional information; unlike the average of two samples with identical methodology. This is just the Popperian paradigm at work.
I agree with this. But in this case, we're talking about aggregators that are attempting to incorporate multiple results into a single one. Maybe that's just not something that's doable in the field right now.
Again, with respect, I think perhaps you do not have sufficient statistical understanding to be able to assess whether his reasoning is poor or not.
No offense taken, but I mentioned a few lines ago that I actually teach statistics at the university level. I certainly don't have political science experience, but the math should still hold.
And this isn't me being particularly favourable to Silver. I think he's terribly smug on Twitter and a very poor quality pundit. I'm just saying that his assumptions are reasonable. Wang thinks that elections are determined to a high degree by a relatively small number of important inputs. Silver thinks that elections are determined to a high degree by a relatively large number of dispersed inputs. Neither of these is better or worse practice; I've seen people argue quite persuasively for both. It's unlikely you could definitely determine which is better because presidential elections aren't actually drawn from the same distribution, you're facing a constantly moving target - presidential elections might, for example, become progressively more dependent on a larger number of inputs over time. So both models can and should co-exist. I think most of the spats between Silver and Wang are just because they're competitors.
My point with the line you quoted me on (about not knowing whether the model is right or not) was agreeing with a good bit of this, but my overall point isn't that his model is bad, but that his defense of his model is bad. I'd be interested in reading a good defense of his model if you have links or papers in some journals, but his defense and explanation is just so terrible. Whether his model works or not is independent of how well he defends it.[/QUOTE]
I think the sharpest criticism you could launch at Silver is something like: the more inputs a model has, the more uncertainty it has. As uncertainty increases, linear estimators tend towards the geometric mean (this has a long explanation, but essentially in a two-person race, it tends towards a 50/50 forecast). A 50/50 forecast implies a 'dead heat'. Dead heats generate the most attention, which translates into money for ESPN. So, Silver isn't creating an inaccurate model, but he might be overly keen to include inputs because the model produces more profitable punditry as a result. But... this is fine, if you just ignore his punditry, which we all should because he can't write anyway.
Here, I disagree. I don't think Silver's problems are as cynical as ESPN influence (I doubt they care at all about the political side of the site at all, really). I just think he's getting a model that's different for the sake of it, and I also think his poor performance during the GOP primary is really tilting him. He's certainly more hostile to criticism now when he should be the opposite (since we have proof that he was very wrong before!). But that's still on his punditry, so I agree there. If you strip out the site's meddling and just look at the numbers, I think they're much better.