Telephone versus Online Survey Modes for Election Studies: Comparing Canadian Public Opinion and Vote Choice in the 2015 Federal Election

Election studies must optimize on sample size, cost and data quality. The 2015 Canadian Election Study was the first CES to employ a full mixed-mode design, aiming to take advantage of the opportunities of each mode while preserving enough commonality to compare them. This paper examines the phone interviews conducted by ISR-York and the online questionnaires from panellists purchased from a sample provider. We compare data quality and representativeness. We conduct a comprehensive comparison of the distributions of responses across modes and a comparative analysis of inferences about voting. We find that the cost/power advantages of the online mode will likely make it the mode of choice for subsequent election studies.