Abstract: A statistical method is developed for efficiently evaluating the response performance of one or more applications, which run in a computer system, under various utilization conditions and within a limited number of experiments. When making multiple load tests corresponding to various application utilization conditions, the method uses a performance monitor tool or a network monitor tool appended to an operating system with a load being applied to the system to first determine the numerical amount of the utilization of applications, numerical amount of the response performance of applications, numerical amount of the utilization of hardware resources, and numerical amount of the response times of hardware resources. Then, estimation expressions are created which describe the dependence among numerical amounts to evaluate the response performance of applications using the estimation expressions.