"Traditional index construction not effective because it makes it difficult for investors to assess source of outperformance."

[COMMENTARY]This interesting article discusses a study which highlights the difficulty in pointing to ESG factors as a standalone factor in ESG fund alpha. The report suggests ESG funds need improved construction to isolate all causes of outperformance.
Report: time to rethink ESG index construction, by Joe McGrath, August 14, 2018, Expert Investor, UK.