The High-Low Index is a market breadth indicator that gauges the strength or weakness of a particular index. It is calculated by dividing new highs by the summation of new highs and new lows, multiplying it by 100 and then plotting a 10 day Simple Moving Average (SMA) of that series to smooth out the values. When the index is above its midpoint of 50, there are more new highs than new lows. When its below 50, there are more new lows than new highs. Values above 70 or below 30 indicate strong uptrends and strong downtrends respectively. The indicator is best used in combination with other analysis techniques.