Abstract: The Social Decision Scheme theory did not take some important factors into account when predicting group decisions. These factors included individual social status, member orientation of individualism and collectivism, distribution of expertise, and so on. In this study, we extended SDS by constructing a Personal Influence Function (PIF) which took the above factors as key elements. In a simulated experiment of investment decision-making, the validity of the extension was tested. The results showed, when PIF combined with group preference distribution, the extended SDS could predict group decisions more effectively and accurately.

Key words: social decision schemes, personal influence function, distribution of preferences