Both Michael Jensen's work and the findings of performance measurement firms such as Becker (Ehrbar 1976) suggested that active, stockpicking investment managers did not outperform stock-market indices systematically. Indeed, once such managers' high costs were taken into account they typically did worse than those indices. … So why not turn Jensen's comparator buying and holding every stock in an index into an investment strategy? If conventional investment analysis had to be "throw[n] away" (McQuown interview) because markets were efficient, then why not simply invest in a portfolio that encompassed the market, for example by including every stock in the S&P 500 index in proportion to its market value?

Donald MacKenzie, An Engine, Not a Camera, loc. 373