Election Update: Clinton’s Big Lead Means A Steadier Forecast

From FiveThirtyEight:

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A friend asked me the other day whether there’s anything preventing Hillary Clinton from rising further in our forecast, beyond what have generally been very good polls for her. Clinton’s chances are up a bit — she’s hit 88 percent in our polls-only forecast, up slightly from 86 percent on Friday and 83 percent a week ago. In the polls-plus forecast, Clinton’s chances are 85 percent, up from 80 percent a week earlier.

But there’s some truth to the notion that she’s encountering diminishing returns. And that’s for a simple reason: 88 percent and 85 percent are already fairly high probabilities. Our model is going to be stingy about assigning those last 10 or 15 percentage points of probability to Clinton as she moves from the steep, middle part of the probability distribution to the flatter part.

Before this turns into too much of a math lesson, a quick review of Monday’s polls. As has often been the case in recent days, they were a mix of catastrophic-seeming results for Trump, mixed in with others that showed a race that remains competitive.

On the not-so-bad side for Trump were a set of polls from CNN that showed him leading by 4 percentage points in Ohio, and trailing Clinton by 2 points in Nevada and 1 point in North Carolina. These polls weren’t great for Trump: None of these are must-win states for Clinton and she was winning two out of three of them despite that. Also, CNN’s polls have been somewhat Republican-leaning this year relative to the polling average. But CNN’s results were consistent with a race in which Trump is trailing …

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