1. A management policy evaluation system constituted by a computer including a processor and a memory, for evaluating a management policy that establishes a rule for assigning an IT resource to be provided in a system that offers service to a user, in accordance with a state of use by the user, the evaluation system comprising: a demand recording part implemented by the memory for recording demand data representing a change in a value of a demand for the service from the user in a predetermined period, the value of the demand being expressed as an operating amount of the IT resource; a supply recording part implemented by the memory for recording supply data representing a change in a value of a supply of the service to be provided by the IT resource to be assigned based on the management policy in the predetermined period, the value of the supply being expressed as the operating amount; a calculation part implemented by the processor for calculating shortage/surplus data representing a change in shortage/surplus of the IT resource with respect to the demand in the predetermined period by using the demand data recorded in the demand recording part and the supply data recorded in the supply recording part; an evaluation part implemented by the processor for converting the change in shortage/surplus of the IT resource represented by the shortage/surplus data calculated by the calculation part into evaluation data representing a quantified business judgment index value; and a value scale data recording part implemented by the memory for recording an association data that associates shortage/surplus of the IT resource with the quantified business judgment index value, wherein the evaluation part converts the shortage/surplus data into the evaluation data using the association data recorded in the value scale data recording part, and wherein the evaluation part generates data representing an amount of opportunity loss as the evaluation data based on, among the shortage/surplus data, data representing a shortage in the value of the supply with respect to the value of the demand, and generates data representing an amount of over-investment as the evaluation based on, among the shortage/surplus data, data representing a surplus in the value of the supply with respect to the value of the demand.