該指標由Alexander Elder博士研發而來，用於測量市場中買方和賣方的壓力。它既可以單獨使用也可以和三重濾網過濾系統結合起來使用。Elder利用13日指數移動平均線（EMA）來反映市場達成的價值共識。牛市力量是用來衡量買方關於推動價格上升達成的共識力量，而熊市力量反映的則是賣方將價格拉低的力量。牛市力量是由當日的最高價減去13日的EMA得出，而熊市力量是由當日的最低價減去13日EMA計算而來。
交易信號
單獨使用的時候，艾達透視指標需要3個窗口：
1. 價格的K線圖以及13日指數移動平均線。
2. 艾達透視指標牛市力量。
3. 艾達透視指標熊市力量。
始終要追隨趨勢交易——趨勢可以通過13日EMA判斷出。
• 當熊市力量位於零以下，並出現看漲背離時做多。
• 牛市力量位於零之上，出現看跌背離時做空。
進一步的交易規則，可以在Elder 博士的《以交易為生》一書中找到。
如果你想實現快速的盈利：
• 每當熊市力量跌破零線之後而向上翻升時增加多頭頭寸。
• 每當牛市力量穿透零線之後反轉為負數時增加空頭頭寸。
示例：
澳大利亞普通股指數以及 13日EMA， 艾達透視指標。
1. [S] 處牛市力量出現看跌背離，做空。等待EMA向下傾斜。
2. [L] 處熊市力量出現看漲背離，做多。等待EMA向上傾斜。
3. 牛市力量出現看跌背離，但此時不建議進場——EMA沒有向下傾斜。
Elder Ray Index
Developed by Dr Alexander Elder, the Elder-ray indicator measures buying and selling pressure in the market. The Elder-ray is often used as part of the Triple Screen trading system but may also be used on its own.
Dr Elder uses a 13-day exponential moving average (EMA) to indicate the market consensus of value. Bull Power measures the ability of buyers to drive prices above the consensus of value. Bear Power reflects the ability of sellers to drive prices below the average consensus of value.
Bull Power is calculated by subtracting the 13-day EMA from the day's High. Bear power subtracts the 13-dayEMA from the day's Low.
Trading Signals
When used on its own, the Elder-ray requires 3 screens:
1. A bar chart with 13-day exponential moving average;
2. Elder Ray Bull Power; and
3. Elder Ray Bear Power.
Only trade in the direction of the trend - indicated by the slope of the 13-day EMA.
• Go long if Bear Power is below zero and there is a bullish divergence.
• Go short if Bull Power is above zero and there is a bearish divergence.
Further trading rules can be found in Trading For A Living by Dr Alexander Elder.
If you wish to pyramid your position:
• Increase your long position whenever Bear Power dips below zero and then rises back into positive.
• Increase your short position whenever Bull Power rises above zero and then falls back into negative.
EXAMPLE
The All Ordinaries Index (Australia) is shown with 13-day exponential moving average (EMA) and Elder Ray Bull & Bear Power.
1. Go short [S] on bearish divergence on Bull Power. Wait for the EMA to turn downwards.
2. Go long [L] on bullish divergence on Bear Power. Wait for the EMA to turn upwards.
3. Bearish divergence on Bull Power but no trade is entered - the EMA does not turn down.
本文翻譯由兄弟財經提供
文章來源：http://www.incrediblecharts.com/indicators/elder_ray_index.php