The House forecast that we released on Friday establishes an over-under line for Republican gains at a net of 47 or 48 seats. But, as I noted at the end of the article, the confidence interval on this forecast is very wide. Its margin of error is about ±30 seats — meaning that a gain of as few as 17 seats, or as many as 78, is entirely possible — and there is a small chance of even larger or smaller gains.
When I noted this on Twitter on Friday, I got a few sarcastic replies: what good is a forecast if it tells you that essentially anything can happen? We’ll return to that question at the end of the article. But first, let’s look at a few numbers.
Currently, the folks at Cook Political consider a total of 87 House races to be either toss-ups or to merely “lean” toward one or the other party. This is an unprecedented number in recent history. At a comparable point in the past six election cycles — that is, with about 25 days to go until the election — Cook Political had put the number of highly competitive races at between 34 and 56; this year’s figure is roughly twice as high.