You can use PredictWise to help make sense of the presidential horse race, but more importantly you can use the data to help you determine how to vote. Now we don’t suggest any candidates for you to support or not, there are plenty of other websites for that, but we can help you figure out how to vote strategically. Voting strategically can be psychologically difficult, sometimes checking the box next to the candidate whose views you don’t like. You need to divorce yourself from the box you check to the action that comes from that vote.

How do you vote strategically? Most likely your individual vote won’t matter at all, but when it does it can matter a lot, and you should vote assuming it does matter. To vote strategically you need to do some research and understand

  • The rules of your primary (The Green Papers is a good source)
  • The current predictions for the primary and the nominations (Predictwise)
  • The markets don’t predict the final percentages well so you may need to check the polls as well.

Let’s look at Arizona and Utah which vote on Tuesday. Spoilers: If you like Trump, vote Trump. If you don’t favor Trump, in Utah vote Cruz and in Arizona vote Cruz if you are a Republican and Clinton if you are a Democrat.

If you are a registered Democrat: Clinton has basically wrapped up the nomination. Utah has open caucuses so if you live in Utah cross over and vote Republican.

Arizona has a closed primary so you can’t cross over. The Democrats in Arizona use proportional representation split between the congressional districts and the state as a whole. Any candidates that doesn’t reach the 15% limit won’t get any delegates, so a vote for anyone other than Clinton or Sanders is a wasted vote.

You are not likely voting on who will win the nomination but when. Vote for Clinton if you want her to wrap up the nomination earlier, vote for Sanders if you want Clinton to wrap up the nomination later. If you prefer Clinton to Trump (who has a 78% chance of being the republican nominee), then you should vote Clinton to end the process earlier and let Clinton focus more on the general election.

If you are voting Republican: Like the Democrats you are not voting for a nominee, rather you are voting for whether Donald Trump wins the nomination on the first ballot of the convention or we have an open brokered convention. Your preference between Cruz and Kasich should not play heavily into your voting strategy.

In Arizona all pledged delegates are allocated to the candidate getting the most votes, 3 for each congressional district and 28 for the whole state. The only true contenders in Arizona are Trump and Cruz. Vote for Trump if you prefer Trump and Cruz if you prefer anyone else. If your particular congressional district has another candidate more likely to win that might change your strategy but that information is hard to figure out and there are more delegates at stake in the statewide count.

Utah uses different rules, if a candidate gets over 50% of the vote that candidate gets all the delegates, otherwise they are split proportionally. Cruz has a big lead and a good chance to reach that 50% mark. This puts Kasich fans in a tough place. Voting Kasich increases the chance that Cruz won’t reach 50% and will allow Kasich to get some delegates. But this will also give Trump some delegates lessening the chance of a brokered convention which is Kasich’s only hope of getting the nomination. So those who like Kasich should bite the bullet and vote Cruz.

Rules do matter. If Arizona had Utah rules, Kasich supporters could guiltlessly vote for Kasich.

If you are a Democrat voting republican in Utah there is an argument that says you should vote for the candidate that is most likely to lose to Clinton (Trump) but Trump has a 24% chance of winning the general election and you need to decide if that’s a risk you can take.

Lance Fortnow is a professor and chair at the School of Computer Science at the Georgia Tech College of Computing