“The most useful part of Dow Theory, and the part that must never be forgotten
for even a day, is the fact that no price movement is worthy of consideration unless the movement is confirmed by both averages. Many who claim an understanding of the Theory consider only the movements of the Industrial stock average if they happen to be trading in industrials. Some even chart only the one average and profess to be able to interpret the movements correctly. It is true that there are times when such conclusions seem justified, but over any extended period such procedure inevitably results in disaster… When the Averages disagree, it’s usually a sign of distribution.”