In Taiwan, the electrical & electronic manufacturing industry, facing very high risks, is very important among the manufacturing industries. The author discusses the reasons for running those various business risks. The original sampling data from the electrical & electronic manufacturing industry of the 1996 industrial census in Taiwan was used. The causal-chains-model was applied to calculate the weighted coefficients of variation of business ratios in causal chains. By ranking those coefficients, the author investigates the acting forces for narrowing the dispersion range of business ratios. At the end, two types of forces were suggested: one is the kind of rules concerning regulation of laws, technical structures, supply and demand of labors, characteristics of production factors, and slowly-changed pattern of markets; the other is the kind of authorities, such as the portfolio selection of optimal assets and synthetic management.