Predictions with multiple components-- if one part fails, overall prediction may still seem true
Nate Silver will make predictions that have multiple components, so that if one part fails, the overall prediction will seem to have come true, even if its coming true had no relation to the reasons Silver originally offered.
See, e.g., "It's a tight race. Clinton's the favorite but close enough that Trump would probably pull ahead if he 'wins' debate." Silver can look back and say "I saw that Trump could pull ahead."
But what he actually predicted was that Trump could pull ahead based on debate performance. If he pulls ahead for some other reason, Silver is completely wrong (because he had excluded that other possibility), yet he seems right.
Via
Nathan J. Robinson, editor of Current Affairs, piles on:
Silver makes sure to hedge every statement carefully so that he can never actually be wrong. And when things don't go his way, he lectures the public on their ignorance of statistics. After all, probability isn't certainty, he didn't say it would definitely happen. And of course, that's completely true. But recognize what it means: even when Silver isn't wrong, because he's hedged everything carefully, he's still not offering any information of value. Sophisticated mathematical modeling, just like punditry, can't tell us much about the things we most need to know. It can't predict the unpredictable, and the unpredictable is what matters most of all.
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Silver is irresponsible and untrustworthy. It's not, as the Huffington Post stupidly alleged, that he's a bad or biased statistician. It's that he mingles solid statistical observations (of highly limited usefulness) with wild prophecy and the same old know-nothing horse-race punditry. He acts as if statistics and polls can tell us to some useful degree whether Trump's highly unorthodox political strategy will work. He offers totally worthless speculative scenarios, such as Bernie Sanders losing all but two states, even though the dynamics that would lead to such scenarios are not accessible to human observation or prediction. And over the course of the election, he used his authority and credibility as a numbers genius to tell people not to worry about Donald Trump, and to treat those who were "freaking out" as if they had were idiots.