How the Senate contest could shake out

Back in 2014, I put together a model to get a sense for how that year’s midterms were likely to play out in the Senate. It used three simple variables: The president’s job approval, whether the incumbent was a member of the president’s party, and whether there was a “problematic” candidate. It suggested that if the president’s job approval were 44 percent, the Democrats would lose nine Senate seats. His job approval was 44 percent, and the Democrats lost nine seats.

I re-ran the model in early 2016. Before I go further, I would direct you to this piece I wrote for Politico Magazine in July, in which I discuss the limitations of predictive models. A lot depends on the subjective assumptions you plug into the models, and I think overall, they should be used as heuristics rather than concrete predictions.

In any event, in early 2016 the model suggested that if the president’s job approval was 52 percent, about where we have it in the RCP Averages, then Democrats should pick up three Senate seats, although potential outcomes range from a loss of one to a gain of eight.