Daily Kos Elections 2016 forecast: Senate numbers jump thanks to North Carolina

One question that we get a lot about our forecast model (and that wasn’t answered as part of our model Q&A that we had a few weeks ago) tends to come from people who look at our map first and start counting electoral votes from there. Take the map above, which you can find on our presidential forecast homepage: It has 273 electoral votes in the “Lean Democratic" category or better banked for Hillary Clinton, in the states that are various shades of blue. That's a win, but it’s sort of the bare minimum, only narrowly clearing 270. That map hasn’t changed much over the last month (if you look back to when we unveiled it on Sept. 9, the only difference among the key swing states was that Nevada was shaded gray).

What causes confusion is that each day we also show a projected electoral vote margin. You can see it in the ticker at the top of the page: On Thursday, it gave 288 EVs to Clinton and just 250 to Donald Trump. The same problem also pops up a lot in our Senate forecast (though not today, as we’ll discuss shortly … which is good news!). Many days, the number of races that show the Democrat with better than 50-50 odds would add up to only 49 seats, and yet we'd be showing a projected result of 50 seats for Team Blue, which makes all the difference in terms of a majority. So why the difference?

What’s happening is that we’re looking at the full range of possible results, and the number we show at the top of the page is the median result of all the thousands of simulations we run. In other words, 50 percent of all of our simulations will end up with more electoral votes than, say, 288, while 50 percent of all of our simulations even up with fewer than 288. It’s not simply what you get when you look at each state individually, and then total up which ones have better than 50 percent odds and which ones have worse.