How Iowa Voted

Democracy is supposed to be simple: The person with the most votes wins. Of course, we know it doesn’t always work that way in the United States. And in tonight’s Democratic caucuses in Iowa, it’s possible that Hillary Clinton will win despite getting fewer votes than Bernie Sanders, or vice versa. How the heck is that possible? The vote percentages reported at the end of the night for the Democrats will be “state delegate equivalents.” There won’t be a raw vote count. Statewide delegate equivalents are, as CNN put it:

The estimated number of delegates to the Iowa Democratic Party’s state convention that a presidential candidate would eventually win, based on the results of the precinct caucuses. This number can then be used to estimate the number of national convention delegates each presidential candidate would eventually win, also based on the results of precinct caucuses.

Is that clear? The number of delegates assigned to each precinct is determined by the number of votes cast for Democratic candidates in recent gubernatorial and presidential elections. So there is a strong connection between the votes that a candidate receives in a caucus and the delegates that he or she wins, but it’s not exact. The most obvious reason that the conversion rate from percentage of raw vote statewide to percentage of statewide delegate equivalents isn’t 1-to-1 is that each candidate needs to reach a minimum 15 percent threshold in each precinct to have a shot at receiving any delegates. That likely means that Martin O’Malley, who is polling well below 15 percent, will end up with a lower percentage of state delegate equivalents than his raw vote percentage. It also means that Clinton and Sanders have a good shot at doing better in their percentage of state equivalent delegates than their raw vote percentage, after O’Malley supporters reallocate when the 15 percent threshold is unmet. The other key reason is that the number of delegates assigned for each precinct is preset. That is, winning all five voters in a precinct assigned 10 delegates is just as good as winning all 100 voters in a precinct assigned 10 delegates. Therefore, for example, it’s possible that Sanders will get a huge surge of college voters in Iowa City (home to the University of Iowa), but the number of delegates he can receive there is fixed. Clinton supporters, on the other hand, may be more evenly spread across the state — in that case, she’ll have more opportunities to pick up delegates in more precincts. So just how much of a difference can all of this make? To see, I looked at Democratic races since 1984 and compared the percentage of state delegate equivalents that was eventually won by each candidate and the corresponding statewide raw vote percentages as estimated from sample precincts (the data is from CBS News, the Voter News Service, Edison Research and the Iowa Democratic Party). The average difference between the estimated raw vote percentage and state delegate equivalent percentage has been 2.1 percentage points per candidate. (A small part of this difference can be assigned to a margin of error. Margins of error differ depending on how much support a candidate earns.) That may not seem like a lot, but if Clinton’s and Sanders’s raw vote percentages equaled their FiveThirtyEight polls-only forecast tonight, a 4.4 percentage point lead by Clinton could actually be a dead heat. Sometimes there can be a very big difference between the estimated raw vote percentage and state delegate equivalent. John Edwards did 6.6 percentage points better in the state delegate equivalent percentage in 2008; that helped him beat Clinton on this measure 29.8 percent to 29.5 percent. That was despite losing to her 27.0 percent to 23.2 percent in estimated raw vote percentage. Four years earlier, John Kerry’s 9.7 percentage point lead over Edwards was cut to just 5.0 percentage points. How the math will work this year won’t be known for a few hours at least. But don’t be surprised if one candidate gets a higher percentage of the state delegate equivalent count than the percentage of people who came out to caucus for him or her.