A method for calculating a sample size for a clinical trial of a first treatment can be provided. The method can include reading a survival curve from a clinical trial for a second treatment, wherein the clinical trial may be selected by a user interacting with a user interface. The method can further include selecting a plurality of points on the survival curve and storing coordinates for each of the plurality of points, wherein the plurality of points are selected so as to capture substantial features of the survival curve. Then, a hazard curve is generated based on the coordinates that were stored, wherein the hazard curve may be a step function. The method can further include calculating a sample size for the clinical trial of the first treatment using a Markov model based on the hazard curve.