This webinar discussed H3ABioNet's experiences with phenotype data harmonization and standards development. It covered both retrospective and prospective harmonization efforts for the H3Africa consortium. Retrospective harmonization involved mapping variables from six cardiovascular disease studies to develop a harmonized CHAIR resource, while prospective efforts involved developing a standardized core set of phenotypes and modules for new studies. Many challenges were encountered, but lessons were learned regarding communicating standards, obtaining clean data, and respecting participant populations. The webinar provided an overview of the harmonization process and acknowledged contributions to the work.