Tactical coalition voting (TCV) is a balancing strategy where voters choose to vote for their second preferred party in order to influence the policy direction of the government coalition formed. In this paper, we experimentally evaluate the extent voters in a PR system engage in TCV. We find significant evidence that voters in the laboratory, even those not experienced with PR systems, choose strategically to affect post election coalitions using a balancing strategy, although the percentage of voters who do so is much less than that predicted by the theory. We also find that although voters who are less informed are less likely to use a balancing strategy, strategic motivations are still a factor in their behavior.