Daily Data Point: Preview 2018 Senate Results with RCP’s Interactive Tool by Sean Trende and David BylerWhat will happen to the Senate next year? This is one of the crucial questions as we start to tiptoe toward the 2018 midterms. Democrats are facing an awful map – not the worst one ever, but one under which we might expect Republicans to make gains in an adequate environment. At the same time, President Trump’s job approval remains mired in the low 40s, although it has bounced back from previous lows in the high 30s.There are signs for hope for both Republicans and Democrats.To help flesh this out, David has created the interactive tool below that is based on a successful approach to estimating elections developed by Sean in the 2014 midterms. Now, usually when people make these sorts of tools, they describe how awesome they are, then add a few caveats at the end about limitations, which everyone then ignores. We believe that the limitations are important, so we are going to state them up front. First, we assume that things will continue to follow previous trends. If the general rate at which factor A affects factor B changes, however, the tool won’t work as well. Trump was an unusual candidate, and has been an unusual president. We might have reason to think that “the old rules don’t apply.” Second, these sorts of tools are only estimates. Like all estimates they have error terms, and if we operate with 95 percent confidence (think of the “plus-or-minus” that accompanies polls), that means we expect one in 20 outcomes to lie outside of that confidence range. In other words, things really do happen on the extremes of probabilities, so just because we might flag an outcome as extremely unlikely does not mean that it won’t happen. As the great statistician G.E.P. Box put it, “[a]ll models are wrong, but some are useful.” We do think this is useful, for reasons we’re about to get to.
Read the rest of the piece and use the interactive here.
Generic Congressional Vote According to a PPP (D) survey:
49% of Americans would vote for a Democrat in the next House of Representatives election, while