An aggregation method includes: acquiring log information including a measurement value of a force used by a processing apparatus and a measurement date and time, the measurement value being measured by a sensor of the processing apparatus that processes a substrate; storing the measurement value of the force and the measurement date and time included in the acquired log information in a storage unit; and integrating the measurement value of the force associated with the measurement date and time in a specified aggregation period with reference to the storage unit to calculate an integrated value of the force for each processing apparatus.