1. A method comprising: measuring a characteristic of an integrated circuit (IC) chip at a plurality of temperatures; modeling to form a hardware model for the characteristic versus temperature based on the measuring; obtaining a known first target value of the characteristic for at least one temperature in the hardware model; determining a plurality of second target values for the characteristic for a corresponding plurality of temperatures in the hardware model; and modeling to form a target model for the characteristic based on the first known target value and the plurality of second target values.