A method includes causing a circuit simulator to perform a circuit simulation using circuit data stored in a storage, the circuit data containing a module to be modeled and a circuit for making a change to a clock to be inputted into the module and clock setting data stored in a storage, the clock setting data being intended to, at a predetermined timing, make a change to the clock to be inputted into the module, and storing a result of the circuit simulation in a simulation result data storage; and generating a hidden markov model about input and output signals of the module from values and times of the signals in accordance with a predetermined algorithm, the values and times being contained in the circuit simulation result stored in the simulation result data storage, and storing data about the model in a hidden markov model data storage.