They should actually regress senator returns against Ken French's research factors [1] and measure the statistical/economic significance of the intercept and the volatility of the residuals.

If I return 2% per year, but do so at 1% volatility and zero market exposure, then I can be a highly successful hedge fund after applying 10x leverage.

[1] https://mba.tuck.dartmouth.edu/pages/faculty/ken.french/data...