This paper presents an intellectual history of the Elections Performance Index (EPI), originally produced by the Pew Charitable Trusts, now produced by the MIT Election Data and Science Lab. The intellectual foundation of the EPI is rooted in two major sources, Heather Gerken’s “Democracy Index” and the work of the Caltech/MIT Voting Technology Project. This paper discusses and six data principles that helped to guide decisions about including particular indicators. It examines changes in EPI index values from 2008 to 2016 to interpret ways in which elections have evolved over the past decade. It concludes by discussing the necessity to revisit some of the EPI’s indicators, in light of changes to voting models and the need to better reflect issues of security and integrity.