In their paper, “Replicating Anomalies,” researchers Kewei Hou, Chen Xue, and Lu Zhang (“HXZ”) looked at 447 factors from quantitative literature to reproduce the outcomes. They found that 286 factors (64%) had no statistical significance. For the 161 factors that appear robust, their magnitudes are less than reported. Specifically, 115/161 don’t have noteworthy “alphas.” Long story short, there doesn’t seem to be many anomalies that can be explained by a factor. However, there are two exceptions: momentum and value.