A contested convention could rattle the Democratic National Convention later this year, according to a prominent political statistician.

FiveThirtyEight’s Nave Silver and his team built two forecasting models for the 2020 Democratic primaries, and one of the options shows a contested convention, meaning that no candidate would have a clear lead going into the nominating event. In this model, no candidate has more than 50% of the delegates ahead of the nomination, and the convention would be used to decide the final candidate, who would not need to be someone already in the race.