stpp calculates the Pohar-Perme non-parametric estimate of marginal relative survival, which under assumptions can be interpreted as marginal net survival. The estimate is a step function and changes at each event time. This is a different implementation to strs and stns where the time-scale is split into a number of intervals. stnet is another command that can be used to give an estimate of marginal relative survival. The motivation for developing stpp was to directly standardize the estimates using both traditional standardization and by using individual weights.