The Quality of Vote Tallies: Causes and Consequences

Abstract

The credibility of election outcomes hinges on the accuracy of vote tallies. We provide causal evidence on the drivers and the downstream consequences of variation in the quality of vote tallies. Using data for the universe of polling stations in Mexico in five national elections, we document that over 40% of polling-station-level tallies display inconsistencies. Our evidence strongly suggests these inconsistencies are nonpartisan. Using data for more than 1.5 million poll workers, we show that lower educational attainment, higher workload, and higher complexity of the tally cause more inconsistencies. Finally, using an original survey of close to 80,000 poll workers together with detailed administrative data, we find that inconsistencies cause recounts and recounts lead to lower trust in electoral institutions. We discuss policy implications.