Jeffrey A. Hirsch, editor in chief of Stock Trader’s Almanac (Wiley), which has been analyzing historical stock market data and patterns for nearly half a century. He also is chief market strategist for Magnet Æ Management, an asset-management firm, White Plains, New York. www.StockTradersAlmanac.com
To predict markets, investors turn not just to official government and business data but also to offbeat indicators that measure…