A screening hit rate divides the number of candidates that pass an agreed test threshold by the number that were tested. In protein design, a hit may be a candidate that shows measurable binding, although the exact threshold, assay conditions, and data-quality rules must be stated for the number to be meaningful.
Hit rate helps compare how efficiently a method produces promising candidates, but it does not describe their final quality by itself. A method can have a useful hit rate while producing binders with weak affinity, poor selectivity, or limited stability, and rates from different experiments are not directly comparable when their tests differ.
ELI5
A screening hit rate tells you how many tested ideas passed the first useful test. It is a fraction or percentage, so both the number of successes and the total number of candidates matter.
For example, if 10 designed proteins are tested and 2 meet the laboratory's binding threshold, the screening hit rate is 20 percent. That number shows how often the screen found an initial success, not whether either protein is ready to become a medicine.
