Differential Scanning Calorimetry (DSC) measurements are routinely used to determine enthalpies of phase change, phase transition temperatures, glass transition temperatures, and heat capacities. In order to obtain data on the amount of phases during phase change, time-temperature lags, which are inherent to the measurement process, must be estimated through a computational analysis. An analytical model is proposed for the systematic error of the instrument. Numerical simulation results are compared against experimental data obtained at different heating and cooling rates.