Criticism of Technical Analysis
Lack of evidence
Although chartists assert that their techniques provide excess returns over time, this assertion is controversial. Many academics believe that technical analysis has no predictive power. Burton Malkiel in his book "A Random Walk Down Wall Street" (8th edition, 2003) and Eugene Fama in "Efficient Capital Markets: A Review of Theory and Empirical Work," May 1970 Journal of Financesummarize many early studies, conducted from the 1950s-70s, that show that after trading costs are considered, the returns generated by many technical strategies underperform a simple buy and hold strategy.
Cheol-Ho Park and Scott H. Irwin reviewed 93 modern studies on the profitability of technical analysis and considered 59 of them to indicate positive results, and 24 negative results. "Despite the positive evidence ... it appears that most empirical studies are subject to various problems in their testing procedures, e.g., data snooping, ex post selection of trading rules or search technologies, and difficulties in estimation of risk and transaction costs."
Critics of technical analysis include well known fundamental analysts. Warren Buffett has exclaimed, "I realized technical analysis didn't work when I turned the charts upside down and didn't get a different answer" and "If past history was all there was to the game, the richest people would be librarians." Still, even an investor like Buffett occasionally recognizes technical analysis. In a recent conference on investing in mining companies, Buffett commented, "In metals and oils, there's been a terrific [price] move. It's like most trends: at the beginning, it's driven by fundamentals, then speculation takes over...then the speculation becomes dominant." To a technician, Buffett basically paraphrased Dow Theory.
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