Application of fuzzy comprehensive evaluation method in investment decision making under the background of digital economy

The digital economy industry is highly dynamic and complex, making it difficult for traditional investment decision-making methods to cope with multi-dimensional fuzzy information and uncertainty. Therefore, this paper proposes a digital economy industry investment decision support system based on fuzzy comprehensive evaluation method (FCE) to improve the scientificity and accuracy of investment decisions. First, this paper analyzes the core characteristics of the digital economy and the complexity of its investment decisions. Combined with relevant literature, this paper sorts out the application status and advantages of investment decision support system (IDSS) and FCE method. Then, a comprehensive decision-making index system is constructed, and the weight distribution of each index is optimised based on correlation analysis, principal component analysis (PCA) and analytic hierarchy process (AHP) to ensure the scientificity and rationality of the model. Subsequently, an investment evaluation model based on FCE is designed to comprehensively evaluate multi-dimensional factors involving market, technology, policy, finance, etc. and the practicality and effectiveness of the system are verified through specific cases. The results show that the system can effectively reduce investment risks and improve decision-making efficiency in a complex and uncertain environment, providing strong support for investment in the digital economy industry.