1. What is the meaning of a four-firm concentration ratio? Interpret what four-firm concentration ratio of 60 % would mean. Interpret what a score of 90% would mean for the four-firm concentration ratio. What are the shortcomings of concentration ratios as measures of monopoly or oligopoly power? For example, take scenario 1- 6 firm's produce 15% each, and the rest is by 10 other firms.