Hit Rate
We define the hit rate of a portfolio as the percentage of positions that have generated positive returns over a given period. For example, over the past year, if 15 positions made money and 5 positions lost money, then the hit rate would be 15/(15 + 5) = 75%.
While this is a common definition in practice, some people only look at closed positions, or use a hurdle rate. The hurdle rate, can be fixed, based on the risk-free rate, or the return of an index.