Does tactical voting matter? The political impact of tactical voting in recent British elections

Although much has been written about tactical voting, few studies have attempted to show its impact on the seat distribution within Parliament and subsequent government makeup in countries with single-member plurality systems. The authors attempt to assess the magnitude and impact of tactical voting in recent British general elections. They build a model of tactical voting by identifying factors known to affect the level of tactical voting measurable using available data. Based on this model, they generate predicted levels of tactical voting for all parties within each district. Based on these predicted values, they adjust actual election data to produce a new set of data containing a would-be election outcome in the absence of tactical voting. By comparing actual election data, adjusted election data, and the seat share of political parties in the parliaments after these elections, they discuss the political impact of tactical voting in the United Kingdom.