Chap 6 on Ben Graham argues value investing doesnt work.
"In 1965, prompted by gains in value stocks and by Samâs
desire to offer clients an alternate rating system, Value Line started selecting the best value stocks in their universe. The firm divided its sample of 1,500 companies into 10 groups based on value, updating the selections each
month. The selection system used the same key variables that
almost everyone else uses to define value stock (i.e., price to
sales, price to book, and price to earnings).
But there was one
difference that today, almost four decades later, makes all the
difference in evaluating the stocksâ long-term performance. In contrast to retrospective
studies of value stocks, the Value Line companies were selected
contemporaneously. Thus, the Value Line value stock performance record is a
real-life unintentional experiment with no back-testing, survivor bias, or armchair quarterbacking.
The procedure has remained the same since 1965"
"We report the results of the experiment in Figure 6.1 and Table 6.2.
Value Line Group 1, consisting mainly of growth stocks, quickly outpaced the
three value stock categories. By March 2002, the growth stocks had returned
almost 28 times the return of the best-performing 'value' group'"
Even though I dont practice value investing what originally prompted my interest on the subject was this
http://www.tweedy.com/resources/library_docs/papers/WhatHasWorkedInInvesting.pdf
It seems that VN is claiming those studies are flawled. Some of the studies do suffer from selective time periods but some of them are free from survivorship bias and some others are quite broad in terms of time. I have no idea what VN means by 'armchair quarterbacking'. At this point I'm uncertain about what to make of the Tweedy studies