Studies about 6 sigma are still in its infant phase because most of them were focused on case studies without sophisticated research models. However, the recent rise of trends adopting 6 sigma as innovative management strategies in leading companies around the globe has made it urgent to develop more academically oriented research model in which 6 sigma activities can be evaluated more rigorously and their relationships with corporate performance can be analyzed more critically. To fill the research void like this, this study proposes a new research model based on cognitive map theory where the 6 sigma project can be evaluated rigorously by considering quantitative and qualitative factors simultaneously, and then the evaluation results can be used to predict the future performance of the project. To fulfill this research intention, this study suggests the following research purposes. First, we summarize evaluation items and methods by using a set of real 6 sigma projects. For this purpose, a number of indepth interviews with 6 sigma experts is performed and organized. Second, current 6 sigma project evaluation process is simply done in a way of summarizing the results from each phase, and then tossing them to the next phase without considering their possible impacts on problem-solving. To overcome this pitfall of the current 6 sigma project evaluation process, we perform a causal relationship analysis of each phase result and its possible links with the 6 sigma project results themselves. In this sense, a fuzzy cognitive map (FCM) is built for the sake of 6 sigma project evaluation through the interviews with field experts. The FCM will be used to evaluate each phase of 6 sigma project before moving to the next phase. Its empirical performance will be measured seriously by the field experts. Third, another group of field experts are invited to evaluate the total performance of the proposed FCM-driven 6 sigma project evaluation process. For this purpose, the proposed research framework is competed with the existing 6 sigma project evaluation methods, acquiring the promising statistical results. Empirical results reveal that the proposed research framework can allow the proposed 6 sigma project evaluation mechanism to be used as a vehicle of boosting the contribution of the 6 sigma projects to corporate performance.