A by-election is a special election in one riding. It is typically held to fill a seat in a legislature that is left vacant by the death or resignation of a member of that legislature, such as a Mayor. By-elections seldom earn much attention beyond the ridings in which they take place. Voter turnout is often lower than in general elections. However, by-elections can be nationally important if a riding switches from one party to another, and if that change alters the balance of power in the House of Commons or a provincial legislature. By-election results can also be important indicators of the popularity of a government, of parties, and of party leaders.