Under our first past the post electoral system, many voters will be looking to cast their vote tactically in order to have the most impact.
Electoral Calculus want to work out the extent to which voters will vote tactically and the parties to whom they will switch allegiance. And whether that changes the outcome in their seat.
This is a fascinating and detailed article which shows the complexity involved and who might or might not vote tactically.
The tactical transition matrix shows which party's voter are more or less likely to vote tactically and who for.
