The Advance/Decline Line ("A/D Line") is undoubtedly the most widely used measure of market breadth. It is a cumulative total of the Advancing-Declining Issues indicator. When compared to the movement of a market index (e.g., Dow Jones Industrials, S&P 500, etc) the A/D Line has proven to be an effective gauge of the stock market's strength. Many investors feel that the A/D Line shows market strength better than more commonly used indices such as the Dow Jones Industrial Average ("DJIA") or the S&P 500 Index. By studying the trend of the A/D Line you can see if the market is in a rising or falling trend, if the trend is still intact, and how long the current trend has prevailed. Another way to use the A/D Line is to look for a divergence between the DJIA (or a similar index) and the A/D Line. Often, an end to a bull market can be forecast when the A/D Line begins to round over while the DJIA is still trying to make new highs. Historically, when a divergence develops between the DJIA and the A/D Line, the DJIA has corrected and gone the direction of the A/D Line. A military analogy is often used when discussing the relationship between the A/D Line and the DJIA. The analogy is that trouble looms when the generals lead (e.g., the DJIA is making new highs) and the troops refuse to follow (e.g., the A/D Line fails to make new highs). Both the Arms Index and Open Arms Index are market indicators that show the relationship between the number of stocks that increase or decrease in price (advancing/declining issues) and the volume associated with stocks that increase or decrease in price (advancing/declining volume). Both indicators are primarily a short-term trading tool, showing whether volume is flowing into advancing or declining stocks. If more volume is associated with advancing stocks than declining stocks, the indexes will be less than 1.0; if more volume is associated with declining stocks, the Index will be greater than 1.0. Both Indexes are usually smoothed with a moving average. The method of smoothing determines whether the indicator is called simply an Arms Index or an Open Arms Index. The former is a simple moving average of the one day calculation. The latter averages the numerator and denominator first before the final calculation. TRIN is a one day Arms Index (not averaged). | 
