Re-Reading "U.S. Equity Styles Indexes" from The Research Foundation of AIMR

I was struck by this blurb within the discussion of the valuation effect on stock over- and under-performance:

"...the surprise registered by academic researchers in response to the discovery
of the value and size effects is hard to overstate. More than a decade of
efficient market and CAPM orthodoxy had convinced most that the cap-weighted
market portfolio could not be beaten, at least not with a simple, easy-to-follow
decision rule..."

The field of investment performance measurement could be said to be as young as the CAPM and efficient market theories were when Reinganum, Banz and Basu discovered the valuation effects. That could indicate there are accepted practices and methodologies within performance measurement and presentation that are currently viewed with similar orthodoxy as the CAPM and efficient market theory were in the late 70s.