民主國家的選舉制度中，選民的政黨認同越強者，越可能進行策略性投票。選民在單一選區的策略投票為黨際間選票之轉移，在複數選區是黨內間之轉移。如果政黨提名多名候選人，政黨認同愈強者，全家越不可能投給同一候選人。不管是在那一種選舉制度之下，對選舉結果越關心者越可能從事策略性投票。觀察國內歷屆行政首長選舉的各政黨得票率之波動程度遠高於複數選區之選舉，不同選制的確造成選民策略投票上的差異。台灣自第七屆（2007）立委選制從廢除SNTV 改採「單一選區兩票制」，是不是會發展出兩黨體制？因此，「杜瓦傑法則」及「策略投票」是觀察台灣的策略投票行為的重要指標。

In the election system of the democratic nation, the political party approbation of the votes is more strong, may carry on a strategy vote more. Votes at single strategy vote of district constituency for the party Ji the ballot transfer, at the plural district constituency is a party inside it transfers. If the political party nominates several candidates, the political party approbation more strong, whole family the more impossible hurl give same candidate. Ignoring is under that election system, concerning more as a result to the election may work on a strategy vote more. Observe each political party of the domestic and successive administration chief election ticket the motion degree of the rate is far high in the election of the plural district constituency, the dissimilarity chooses the difference that system really causes the votes strategy vote. Does Taiwan choose system to change to adopt “single district constituency two ticket systems”, would develop two party systems from the abrogation SNTV from the seventh (2007) legislator? Therefore, “Duverger’s Law " and "strategic voting” is the important index sign of the strategy vote behavior that observes Taiwan.