P/E expansion and contraction

Vitaliy Katsenelson writes in "Active Value Investing"

...I wanted to see what would happen to the average P/E of each quintile if I bought each quintile in the beginning of the range-bound market (January 1966) and sold it at the end in December 1982...The highest-P/E quintile exhibited a P/E compression of 50.3 percent. The P/E of the average stock dropped from 29.3 in 1966 to 14.6 in 1982. That portfolio generated a total annual return of 8.6 percent. The lowest-P/E quintile to my surprise had a P/E expansion of 34.8 percent. Yes, you read it right. The P/E of the average stock in my lowest-P/E quintile actually went up from 11.8 to 15.8 throughout the range-bound market. That portfolio produced a nice bull market-like total annual return of 14.16 percent...

see also

Tweedy Browne's What Has Worked In Investing (page 23)

According to What Works on Wall Street, low PERs worked well with big stocks, but not with small stocks.