Donaldson Capital Management, a regional money management firm, manages nearly $400 million allocated among three investment managers. All portfolios have the same objective, which is to produce superior risk-adjusted returns (by beating the market) for their clients. You have been hired as a consultant to measure the performance of the portfolio managers. You have collected the following information based on the last ten years of returns.

Portfolio Manager	Mean Annualized Rate of Return	Beta	Standard Deviation of Return
a	0.18	1.35	0.24
b	0.21	1.95	0.25
c	0.24	2.10	0.22

During the same time period the average annual rate of return on the market portfolio was 13% with a standard deviation of 19%. In order to assess the portfolio performance of the above managers, you should use: