Can you benchmark an index against another index?

Investors use an index as a point of reference to compare how well their investments are doing. For example, an investor holding individual common stocks can compare his performance to a wide based benchmark index such as the S&P 500. An investor can also benchmark one index against another to compare relative performance of a specific Stock Market sector. For example, a benchmark index for gold can be compared to a benchmark index for oil or real estate to evaluate the relative performance return of each sector.