立法委員的立法參與包括正式與非正式兩個部分，前者是指立法委員參與在正式立法程序中的行為，包括出席、提案、連署、發言、表決等，至於後者是指在法案正式進入立法程序之前或之後，立法委員為了促使法案的通過或不通過，而在非正式立法程序中所表現的行為，例如勸導說服、協調溝通、談判妥協、甚至是威脅利誘的行為。一般對於立法參與的研究多半限於正式的立法參與部分，然而，如果立委的正式參與與非正式參與行為之間有很大的差異，則只觀察正式立法參與可能無法盡得全貌，甚至將會誤導研究的結果。本研究乃以立法參與為探索目標，主要探索重點在於：第一、立委的正式與非正式參與行為之間的關連性如何？究竟立委講哪些法案上正式與非正式的參與較為一致？又是在哪些法案上歧異較大？第二，立委的正式與非正式參與是受到哪些因素的影響？究竟政黨、法案種類、以及立委個人的特質對正式與非正式立法參與的影響是否有所不同？第三，尋找觀察與測量立委正式與非正式立法參與的可行方法，以作為後續研究的參考。

　　　　　There are two modes of legislative participation: formal and informal. The former is the both public and formal behavior of legislators in the legislative process - including initiating, sponsoring, speaking, and voting. The latter mode of participation relates to those activities behind the scene - including persuasion, negotiation, threats, and seduction. Most research focuses only on the formal part of legislative participation. If there exists a striking discrepancy between formal and informal participation, however, those focusing only on the formal part may not observe the whole picture of legislators' participation in the legislative process. There are three major purposes to this exploratory research. The first is to uncover the relationship between formal and informal participation across different bill categories. The second is to uncover the influential factors in legislators' formal and informal participation. Do parties, bill categories, and legislator chacteristics affect legislators' formal and informal participation in different ways and degrees? The third purpose is to discuss appropriate methods to observe and measure formal and informal legislative participation for future studies.