Information ratio

The Information ratio is a measure of the risk-adjusted return of a financial security (or asset or portfolio). It is also known as Appraisal ratio and is defined as expected active return divided by tracking error, where active return is the difference between the return of the security and the return of a selected benchmark index, and tracking error is the standard deviation of the active return; i.e., the information ratio is:

where is the portfolio return, is the benchmark return, is the expected value of the active return, and is the standard deviation of the active return, which is an alternate definition of the aforementioned tracking error.

Note in this case, is defined as excess return, not the risk-adjusted excess return or Jensen's alpha calculated using regression analysis. Some analysts, however, do use Jensen's alpha for the numerator and a regression-adjusted tracking error for the denominator (this version of the information ratio is often described as the appraisal ratio to differentiate it from the more common definition).