Nice article with deep factor analysis of Buffett's alpha. What I do not understand at all: Why is there "a lack of alpha"? Did it not clearly show up by these sophisticated factor evolutions over time, expressing real mastery? And if there is a lack, why "selecting factors and combining them into multi-factor portfolios is a challenging endeavor"? If there were "a lack of alpha", then it would have been plain passive investing, what Buffett did!?

Or are these contradictions another "feature not a bug" as is the case with the whole factor theory, which one of the most successful HF managers and deep thinker David Harding calls "hardly the height of good scientific practice", because it is just "retrospectively introducing extra variables and fitting the data to them" as has obviously been done here as well? See: https://www.winton.com/davids-views/July-2018/wintons-david-harding-on-…