The two most common models for incomplete data with a known truncations point are the truncated and censored Gaussian models. These kinds of models were introduced in pharmacometrics in Stuart L Beal (2001) for handling data below the limit of quantification. The paper used the name M2 for the truncated model and M3 for the censored model. In this webinar, we introduce you to the science of handling truncated and censored data models. Further, we show an implementation in Pumas and discuss the certain post-processing features that may be useful to understand the impact of such models.