Why Buenos Aires Voters Avoided Strategic Voting in the 2013 Senate Race

Why Study Voter Strategy in Buenos Aires?

Lucas Núñez examines whether Argentine voters cast ballots strategically or expressively in the 2013 Senate election for the City of Buenos Aires. The question matters because many models of electoral behavior predict that voters facing the risk of wasted votes will shift their choices between a primary and a general election to influence outcomes, but actual behavior in multi-stage and fragmented party systems is unevenly observed.

How Strategic Behavior Is Measured

The study reconstructs a voter transition matrix between the primary and the general election using a rich set of ballot-box returns. Núñez applies a Bayesian hierarchical model for ecological inference to recover individual-level switching patterns from aggregate precinct-level data. This approach estimates how groups of voters moved (or did not move) across party lines between the two voting rounds while accounting for variation across polling places.

Key Findings

• Strategic voting was uncommon in Buenos Aires: at least 75% of voters who had a realistic opportunity to avoid wasting their vote by switching did not do so.
• Analysis of other provinces in the same election cycle reveals high levels of vote wasting outside Buenos Aires as well.
• The results are consistent with electorates composed of mixed motivations: a minority of strategically motivated voters coexists with a larger expressive faction that prioritizes identity, signaling, or sincere preference over instrumental impact.

What This Suggests for Electoral Behavior

These findings challenge simple expectations from instrumental voting models in contexts with primaries and multiple parties. When expressive motivations dominate, voters are less likely to consolidate behind viable contenders between rounds, producing persistent vote wasting and affecting party fortunes. Núñez's use of ecological inference on ballot-box data demonstrates a scalable way to assess these dynamics where individual-level survey data are limited.

Who Should Care

Scholars of voting behavior, party strategy, and electoral institutions will find these results relevant for understanding vote coordination problems in fragmented systems and for interpreting aggregate election outcomes in Argentina and comparable democracies.