Stirred tank bioreactors are commonly used in making biopharmaceuticals, but different designs can affect how well they work. To compare them accurately, we need standardized ways to test them. It's also important to see how well they grow bacteria, yeast, and animal cells. By using consistent methods to test both the engineering and biological aspects of bioreactors, we can quickly see if they are suitable for use. This helps in developing better bioreactor systems for large-scale production.