This report was made possible by The Pew Charitable Trusts. Pew Research Center is a subsidiary of The Pew Charitable Trusts, its primary funder.

This report is a collaborative effort based on the input and analysis of the following individuals:

Research team           

Ruth Igielnik, Research Associate
Scott Keeter, Senior Survey Advisor
Courtney Kennedy, Director, Survey Research
Bradley Spahn, Stanford University
Nick Hatley Research Analyst
Arnold Lau, Research Analyst
Andrew Mercer, Senior Research Methodologist
Nick Bertoni Panel Manager
Elliott Morris, University of Texas

Communications and editorial

Rachel Weisel, Communications Manager
Hannah Klein, Communications Associate
Travis Mitchell, Digital Producer, Copy Editor
David Kent, Copy Editor

Graphic design 

Bill Webster, Information Graphics Designer

Colleagues from across Pew Research Center contributed greatly to the development and execution of this report. We would especially like to thank Claudia Deane, Michael Dimock and Jocelyn Kiley for their editorial contributions. In addition, several practitioners and other experts provided helpful guidance and advice, including Whit Ayres, David Becker, Kevin Collins, Ken Goldstein, Hannah Hartig, Eitan Hersh, Dan Judy, Jon McHenry and Bill McInturff.

We offer special thanks to staff from the five voter file vendors who helped us better understand their products and cheerfully and patiently responded to our numerous questions and requests.