平均動向指標是Welles Wilder發明的定向運動系統指標的一部分，它可以顯示股價是處於調整期還是趨勢中。
ADX 信號
趨勢改變
當14日ADX指標線走勢向下，但在40之上時說明趨勢走弱。需要註意的是，ADX指標只是顯示趨勢的強弱——而不是趨勢的方向。建議您將它配合別的趨勢指標使用，比如動向指標或者移動平均線等。
市場處於趨勢中還是調整期
• ADX低於20說明市場處於調整期；
• ADX 大於20且向上增長，顯示一個新趨勢的開始；
• 如果ADX突破後緊接著一個失敗的反彈，說明趨勢在加強。
• ADX大於40顯示趨勢陡峭上升，但接下來通常會面臨一輪反彈。
示例
蘋果公司股票[AAPL]及其對應的平均動向指標（14天）和14天動能擺蕩指標。
1. 當ADX大於20，動能擺蕩指標低於0時做空。
2. ADX 大於 40，但走勢向下，預警趨勢減弱。
3. 動能擺蕩指標向上穿過0時平倉。
4. ADX 一直維持 20以下，顯示市場處於調整期。
5. 動能擺蕩指標大於0、ADX 向上穿過20時做多。
6. 當 ADX重新恢複在20之上，動能擺蕩指標仍然大於0時加倉做多。
7. 動能擺蕩指標向下穿過0時平倉。
ADX - Average Directional Index
ADX is part of the Directional Movement System developed by J. Welles Wilder but can be successfully used on its own to signal trend changes and to indicate whether a stock is trending or ranging.
ADX Signals
Trend Changes
A weakening trend is signaled when 14-day ADX turns down while above 40. Note that ADX only indicates trend strength — not trend direction. It may be wise to supplement ADX with a trend filter, whether directional movement or a moving average, to signal direction.
Trending or Ranging Markets
• ADX below 20 for any length of time indicates a ranging market;
• ADX rising above 20 indicates the start of a new trend;
• The trend signal is strengthened if ADX breakout is followed by a failed swing;
• ADX above 40 indicates a steep trend, but often precedes a reversal.
EXAMPLE
Apple Inc. [AAPL] is displayed with Average Directional Index (14 days) and 14-day Twiggs Momentum as a trend filter.
1. Go short when ADX rises above 20 and Momentum is below zero.
2. ADX down-turn above 40 warns that the trend is weakening.
3. Exit when Momentum crosses above zero.
4. ADX holding below 20 indicates a ranging market.
5. Go long when ADX rises above 20 and Momentum is above zero.
6. Increase position when ADX recovers above 20 and Momentum still above zero.
7. Exit when Momentum crosses below zero.
本文翻譯由兄弟財經提供
文章來源：http://www.incrediblecharts.com/indicators/adx-average_directional_index.php