Editing By-election (section)

=== Indirect impact ===
[[File:MaryEllenSmith1918SunsetMag.tif|thumb|200px|[[Mary Ellen Smith]] became the first woman in the [[Legislative Assembly of British Columbia]] in a 1918 by-election, the first election in which women of the province could vote.<ref>{{cite web |url=https://www.leg.bc.ca/dyl/Pages/1917-Women-Win-the-Right-to-Vote.aspx |title=1917 – Women Win the Right to Vote |website=Legislative Assembly of British Columbia}}</ref>]]
By-election upsets can have a psychological impact by creating a sense of momentum for one party or a sense of impending defeat for a government. For example, in Canada, [[Deborah Grey]]'s [[1989 Beaver River federal by-election|1989 by-election victory]] in [[Beaver River (federal electoral district)|Beaver River]] was seen as evidence that the newly formed [[Reform Party of Canada]] would be a serious political contender and that it posed a serious political threat for the ruling [[Progressive Conservative Party of Canada|Progressive Conservatives]]. Similarly, the upset 1960 by-election victory of [[Walter Pitman]] in [[Peterborough (electoral district)|Peterborough]] as a "[[New Party (Canada)|New Party]]" candidate was a significant boost for the movement to replace the [[Co-operative Commonwealth Federation]] with an unnamed "New Party" which would be integrated with the labour movement. Pitman's candidacy in a riding in which the CCF was traditionally weak was seen as a test of this concept, and his upset victory convinced the CCF and the labour movement to launch the [[New Democratic Party]] (NDP). [[Gilles Duceppe]]'s 1990 upset landslide by-election victory in [[Laurier—Sainte-Marie]] with 66% of the vote on behalf of the newly formed [[Bloc Québécois]] was the first electoral test for what was initially a loose parliamentary formation created two months earlier after several Quebec MPs defected from the Progressive Conservative and Liberal parties to protest the failure of the [[Meech Lake Accord]] and provided the first indication that the party could be a serious force in the province of Quebec. On the strength of the by-election victory, the BQ went on to be officially formed as a party in 1991 and win 54 seats in the 1993 federal election, enough to form the Official Opposition.

By-elections may occur singly or in small bunches, especially if the authority responsible for calling them has discretion over the timing and can procrastinate. They are sometimes bunched to save money, as holding multiple by-elections is likely to cost more than holding a by-election to fill the vacancies all at once. In Canada, in 1978, [[By-elections to the 30th Canadian Parliament|15 by-elections were held on a single date]], restoring the House of Commons to 264 members. The media called it a "mini-election", a test of the Liberal government's popularity with a general election due in less than a year. In Hong Kong, in January 2010, five members of the Legislative Council from the [[Pro-democracy camp]], one from each of Hong Kong's five geographical constituencies, resigned and stood in simultaneous by-elections, at which the entire electorate would participate, in an attempt to stage a [[Five Constituencies Referendum|de facto referendum]] on democratizing the Hong Kong political system. The effect of the manoeuvre was blunted when the [[Pro-Beijing camp]] refused to stand candidates against them.