Robustness of Smart Beta Strategies.

Summary There has been significant evidence that systematic equity investment strategies (so-called smart beta strategies) outperform the cap-weighted benchmarks in the long run. These strategies are usually marketed on the basis of outperformance. However, it is important to recognize that performance analysis is typically conducted on backtests that apply the smart beta methodology to historical stock returns. Concerning actual investment decisions, a relevant question is: How robust is the outperformance? The issue of robustness, as in extreme risk and performance attribution to well-defined risk factors, is not dealt with by index providers despite investors being wary of robustness of outperformance of various smart beta strategies. This article, with the use of single- and multi-factor indices, examines the causes of, and remedies for, lack of robustness and then provides a framework to evaluate the robustness of various smart beta strategies.