區域立法委員選舉選區席次愈大，正面的影響是選舉結果的公平性愈大〈席次比例性愈大〉，國會愈能有各黨派的聲音；反面的影響是政黨、候選人與投票人所面對選舉的複雜度愈大，國會愈不能穩定運作。我們希望選舉結果的公平性愈大，但也希望選舉的複雜度愈小；另外，我們希望國會能有各黨派的聲音，但也希望國會能穩定運作。可是以上之目的相互衝突，因此如何決定「合適選區席次」是一個重要的議題。目前中央選舉委員會選舉資料庫存有歷屆立法委員選舉各候選人在各投票所之得票數資料，我們無法直接利用這些資料產生可供「合適選區席次」決定之參考指標，但可在一些簡單的假設前提下，利用這些資料作各種選區席次之模擬選舉，由模擬選舉結果產生之指標則可供決策參考。本研究說明模擬選舉的方法與如何由模擬選舉結果產生之指標決定「合適選區席次」，並得到「合適選區席次」爲4席之結論。

In constituency legislator election, for the positive side, the bigger the electoral district seat is, the higher the fairness of the election result is, and the more the voices of various parties and groups in congress are. However, for the negative side, the bigger the electoral district seat is, the higher the order of the election complexity that the political party, the candidate and the voter have to face is, and the less the efficient of the congress' operation is. We hope that the fairness of the election result is higher, but also hope that the order of the election complexity is lower. Moreover, we hope that the voices of various parties and groups in congress are more, but also hope that the efficient of the congress' operation is more. But the above goals conflicts mutually. Therefore, how to decide "the appropriate electoral district seat" is an important subject.At present, the data bank of the Central Election Commission keeps all the vote data of each candidate in every voting station for previous legislative elections. It is difficult to find out any usable indicators for deciding "the appropriate electoral district seat" by directly assembling the above existing data. However, under several simple presumptions, simulating elections can be conducted on the existing data with various district seats. Those indicators generated from simulation results can be useful as reference in decision-making. This study explains how to conduct the simulating elections and how to decide "the appropriate electoral district seat" with indexes generated from the results of simulating elections. It shows that 4 seats is an appropriate district seat.