「行政部門委員會」意指行政部門內針對特定政策或重大議題進行審議和協商的合議制組織，其決策者包含行政官員、專家學者以及相關團體代表。儘管利害關係人可透過委員會增加政策參與的機會，但也引發許多對參與程序和成效的批判。依此，本文試圖說明：委員會作為公共參與的重要機制，是否真能提升利害關係團體的效能感。為更深入分析參與對效能感的作用，作者將參與細分為制度與行為兩層次；效能感則以行政效能感、民主效能感和實質效能感三個次構面組成。本文以全民健康保險會為研究案例，透過健保的利害關係人問卷以及會議記錄編碼，分析利害關係人的委員會參與對效能感有何影響。研究結果發現：三項效能感皆傾向正面評價，民主效能感最高，行政效能感最低。就參與作用而言，出席次數愈多，三項效能感評價愈高；但發言和提案則分別對行政效能感和實質效能感呈現負相關。由此反映出委員會參與的本質：無論與會者對委員會的行政或民主功能多悲觀，制度賦權仍舊對實質效能感具有正面影響。然而，把參與成本和決策結果納入考量後，對委員會參與的規範性期待，將趨向政治利益的實務考量。

“Governmental committees” are a type of collegial organization for negotiation and deliberation of critical policies in the executive branch, whereas decision makers are bureaucrats, experts and representatives of related groups. Although the stakeholders can strengthen the opportunity of policy participation through governmental committees, they are often criticized for their participatory procedures and outcomes. Thus, the aim of this research is to explore whether committee participation can improve the efficacy of stakeholder groups. In order to elaborate the impact of participation on the efficacy of stakeholders, in this study, the concept of participation is divided into the institutional and behavioral levels, while stakeholders’ efficacy is discussed on administrative, democratic, and substantive sub-dimensions. By analyzing the survey of stakeholders and the meeting minutes of the National Health Insurance Committee, this study attempts to illustrate the relationship between participation and efficacy. The results are illustrated as follows: Three sub-dimensions of efficacy are more positive than negative. The democratic dimension holds the highest rating while the substantive efficacy is the lowest. In terms of participative behavior, the frequency of attendance is significantly positive correlated to the three efficacies. However, the statement and proposal variables separately result in negative outcomes of the administrative and substantive efficacy. These findings uncover the nature of committee participation: Regardless of whether participants are skeptical of the administrative and democratic function of governmental committees or not, the institutional factor has a positive effect, meaning empowered groups have positive feedback on substantive efficacy. Nevertheless, after the participatory cost and decision outcome are taken into account, the stakeholders’ normative expectations of governmental committees are transferred to the pursuit of substantive political interests.