Their purpose is the sameto determine a partys nominee (by determining which candidates slate of delegates will get to go to the party convention, with the ultimate goal of deciding the partys nominee). The difference is in how these contests are conducted, Dr. Callahan Harrison says. Starting in 2020, most states (44) hold primaries where voters go into a voting booth and cast a ballot for the candidate of their choice, Dr. Pybas says. However six states (Iowa and Nevada, Kansas, North Dakota, Wyoming, and Maine) will hold a caucus which is a special meeting where voters get together to discuss candidates, debate issues, and choose the delegates.

The caucus system is a little more complicated than a primary which is why more states are moving away from them, he adds.