Process analytical technology (PAT) initiatives are now an integral part of developmental efforts in the pharmaceutical industry. Many technical and scientific papers and even dedicated sections appear regularly in several pharmaceutical manufacturing publications. They may be part of a quality by design (QbD) project to better identify and understand critical process parameters. The need and plus value of PAT is usually well-recognised and understood through establishment of the design space of a unit process. However, monitoring and control methodology and PAT protocols are still undefined, and there is no global consensus yet. It is on these grounds that ASTM started working groups focusing on the elaboration of standards in model building and process monitoring with PAT.