Information Ratio Calculation for Portfolio Performance

John is a portfolio manager who oversees a mutual fund with an objective to outperform its benchmark index. At the end of the year, John's fund has a return of 12%, while the benchmark index has returned 8%. To evaluate John's performance relative to the benchmark, he decides to calculate the information ratio. The information ratio is defined as the active return divided by the tracking error.

The active return is the difference between the fund's return and the benchmark return, and the tracking error measures the volatility of the difference between the fund's returns and the benchmark's returns.

What is the value of the information ratio that John will compute for his mutual fund?