This chapter is concerned with the use of Bayesian methods to aid critical quality attribute identification, development of design space, and process validation. It discusses frequentist statistical methods for the sake of providing the context for Bayesian alternatives. The chapter demonstrates how to link oncogenicity of residual host cell DNA, which is often a critical quality, attributes, to clinical safety. It argues that a process employs an enzyme to fragment residual DNA in the product. Process development for biopharmaceuticals consists of upstream and downstream developments. Process development is known to be labor intensive and time consuming, as a series of experiments need to be carried out to optimize the upstream and downstream developments. The implementation of control strategies enables a manufacturing process to consistently deliver a quality product. Process validation is a regulatory requirement, intended to demonstrate that a process can consistently produce batches meeting quality standards.