The Dow theory is an approach to trading developed by Charles H. Dow, who with Edward Jones and Charles Bergstresser founded Dow Jones & Company Inc. and developed the Dow Jones Industrial Average.The market trend can be analysed by daily line charts with 2 years of data using Dow Theory.In the chart, need to mark the tops and bottoms.The major draw back of Dow theory is, it does not explain the price behavior of the stock/securities.