Average Directional Movement Index Technical Indicator (ADX)

Average Directional Movement Index Technical Indicator (ADX) helps to determine if there is a price trend. It was developed and described in detail by Welles Wilder in his book “New concepts in technical trading systems”.
However, the main purpose of the ADX is to determine whether a stock, future, or currency pair is trending or is in a trading range. Determining which mode a market is in is helpful because it can guide a trader to which other technical analysis indicators to use.

Calculation
ADX = SUM[(+DI-(-DI))/(+DI+(-DI)), N]/N

Where:
N — the number of periods used in the calculation.

The scale for the DMI is from 0 to 100. The average directional movement index (ADX) is a moving average of the DMI.

The first concept to remember is that the direction that the ADX moves doesn’t depend upon the direction of the underlying stock. All the ADX shows is the trend strength.

1. Strong upward trend of stock = Increasing ADX
2. Strong downward trend = Increasing ADX

The ADX is so popular because determining whether a stock, commodity, or currency market is trending or not trending can help a trader avoid the pitfalls of some indicators.

Moving Averages
Moving averages and their variants are effective during trending markets; however, during consolidation periods when prices go up and down, but in no direction, moving average indicators have a tendency to give numerous false buy and sell signals that add up to trading losses. During trending markets, use moving averages, trendlines, and other trend following technical indicators.

Oscillators
Oscillators are extremely effective in non-trending markets. Buying low and selling high is accomplished quite readily with oscillators. Unfortunately, during trending markets, oscillators perform quite poorly, often selling short during a bull market run or buying during a bear market downtrend, adding up to large losses. For periods of non-trending, use oscillators like Stochastic Fast & Slow, RSI, or Williams %R and other range-bound indicators like Bollinger Bands or Moving Average Envelopes.