According to a well-recited traders’ omen, "As January goes, so goes the year." The so-called January Barometer, as first mentioned by Yale Hirsch of the Stock Trader’s Almanac, suggests the performance of stocks in the first month of the year dictates where prices will head for the year overall. And January went quite well, with the S&P 500 starting 2013 up over 5%, its best gain for this seemingly powerful and predictive month in 15 years. Followers of this "fortune-telling" mechanism might be excited . . . but does it really work?