Systems and methods compute a mean timing value of an integrated circuit design for variables using a first timing calculation of relatively higher accuracy; and calculate a first timing value of the integrated circuit design for the variables, using a second timing calculation having a relatively lower accuracy. Such systems and methods calculate second timing values of the integrated circuit design for additional sets of variables using the second timing calculation; and calculate finite differences of each of the second timing values to the first timing value. Thus, these systems and methods calculate a statistical sensitivity of the first timing value to the additional sets of variables based on the finite differences. Further, such systems and methods calculate a statistical sensitivity of the mean timing value to the additional sets of values based on the statistical sensitivity of the first timing value to the additional sets of values.