{Reference Type}: Journal Article {Title}: Potency Assay Variability Estimation in Practice. {Author}: Li H;Witkos TM;Umlauf S;Thompson C; {Journal}: Pharm Stat {Volume}: 0 {Issue}: 0 {Year}: 2024 Jul 8 {Factor}: 1.234 {DOI}: 10.1002/pst.2408 {Abstract}: During the drug development process, testing potency plays an important role in the quality assessment required for the manufacturing and marketing of biologics. Due to multiple operational and biological factors, higher variability is usually observed in bioassays compared with physicochemical methods. In this paper, we discuss different sources of bioassay variability and how this variability can be statistically estimated. In addition, we propose an algorithm to estimate the variability of reportable results associated with different numbers of runs and their corresponding OOS rates under a given specification. Numerical experiments are conducted on multiple assay formats to elucidate the empirical distribution of bioassay variability.