The first experiment in political science is regarded to be Harold Gosnell's 1924 study on voter turnout in Chicago. In this experiment, he randomly assigned districts to receive information on voter registration and encouragements to vote. Current experts in experimental methodology in political science include Rebecca Morton and Donald Green. Since then, experimental research has become a growing area of political science. The publication of experimental research articles in flagship political science journals has risen, especially since the 1980s. Moreover, citation analysis indicates that articles using experimental methods have higher rates of citation.