Understanding the ADX Indicator: An Introduction to the ADX

8 de mai. de 2023

The Average Directional Index (ADX) is a technical analysis indicator that helps traders determine the strength of a market trend. Developed by J. Welles Wilder in 1978, the ADX has become a popular tool amongst traders for assessing the overall trend strength in any financial market, be it stocks, forex, or cryptocurrencies. In this blog post, we will cover the basics of the ADX indicator, its calculation, and how to use it effectively in your trading strategy.

What is the ADX Indicator?
The ADX is a non-directional indicator, meaning it doesn't indicate the direction of a trend, but rather its strength. It ranges from 0 to 100, with values below 20 generally considered to indicate weak or non-existent trends and values above 40 indicating strong trends. The ADX is often used in conjunction with other directional indicators, such as the Positive Directional Indicator (+DI) and the Negative Directional Indicator (-DI), to determine the direction of a trend.
How is the ADX Calculated?
The ADX is derived from two other indicators created by Wilder: the +DI and -DI. These are calculated using the following steps:

1. Calculate the True Range (TR): The TR is the largest of the following three values:
a. The current High minus the current Low
b. The absolute value of the current High minus the previous Close
c. The absolute value of the current Low minus the previous Close

2. Calculate the Directional Movement (DM): The DM is the difference between the current High and the previous High (+DM) or the current Low and the previous Low (-DM), depending on which is larger. If neither is larger, DM is set to zero.

3. Calculate the Smoothed TR and DM values: The smoothed values are calculated using an exponential moving average (EMA) with a specified period (usually 14).

4. Calculate the +DI and -DI: Divide the smoothed +DM and -DM by the smoothed TR to get the +DI and -DI.

5. Calculate the Directional Movement Index (DX): The DX is calculated using the following formula:
DX = (|+DI - -DI| / (+DI + -DI)) * 100

6. Calculate the ADX: The ADX is the EMA of the DX values, typically using a 14-period EMA.

How to Use the ADX Indicator in Trading
Now that we know how the ADX is calculated, let's discuss how to use it in your trading strategy. Here are some tips for using the ADX:

Identify Trend Strength: The primary purpose of the ADX is to determine whether a market is trending. If the ADX is above 20, it suggests that the market is in a strong trend, whereas values below 20 indicate that the market is range-bound or has a weak trend.

Determine Trend Direction: Although the ADX itself does not indicate trend direction, combining it with the +DI and -DI can help you determine the direction of a trend. If the +DI is above the -DI, it suggests that the market is in an uptrend, and conversely, if the -DI is above the +DI, it indicates a downtrend.

Use ADX for Entry and Exit Signals: The ADX can be used to generate entry and exit signals. For example, a trader might enter a long position when the ADX is above 20, and the +DI crosses above the -DI. Conversely, a short position might be entered when the ADX is above 20 and the -DI crosses above the +DI.

Filter False Breakouts: The ADX can help you filter false breakouts by ensuring that the market is in a strong trend before entering a trade. For example, if a breakout from a support or resistance level occurs while the ADX is below 20, it might signal a false breakout, and the trader should wait for the ADX to rise above 20 before entering the trade.
Combine with Other Indicators: The ADX works well when used in conjunction with other technical analysis tools, such as moving averages, oscillators, or chart patterns. Combining multiple indicators can help improve the accuracy and reliability of your trading signals.

Conclusion
The Average Directional Index (ADX) is a valuable tool for traders to assess the strength of market trends. By understanding how the ADX is calculated and using it effectively in your trading strategy, you can better identify strong trends, determine their direction, and generate more reliable entry and exit signals. Keep in mind that the ADX is just one of many technical indicators available to traders, and it's essential to combine it with other tools and techniques to create a well-rounded and effective trading strategy.