An investor is comparing the performances of two portfolio managers who have been allocated an equal amount of investment funds. The managers apply the same strategy with the same constraints, and their portfolios are not diversified. The investor gathers the following data about the two managers and the market index:

| | Manager 1 | Manager 2 | Market index |

|---------------------|-----------|-----------|--------------|

| Average return | 32% | 28% | 22% |

| Beta with respect to market index | 1.2 | 1.4 | 1.0 |

| Standard deviation of returns | 18% | 14% | 10% |

| Tracking error | 8% | 6% | 0% |

The risk-free rate of interest is 3%. Which of the following is an appropriate measure to use and the correct conclusion to reach when comparing the performances of the two managers?