The triple screen trading system is based on employing the best of both the trend-following indicators and oscillators to make trading decisions. Traders are primarily concerned with any realized divergences between the readings of a longer-term trend-following indicator such as a weekly moving average convergence divergence (MACD) histogram and the relatively shorter-term reading from an oscillator such as force index, Elder-Ray, stochastic or Williams %R.
Second Screen - Elder-Ray
Elder-Ray, devised by Dr. Alexander Elder, is based on the concepts of bull power and bear power, the relative strength of bulls and bears in the market. Bull power measures the ability of market bulls to push prices above the average consensus of value, which is the actual price at which a particular stock happens to be trading for a given point in time. Bear power is the bears' ability to drive prices lower than current prices, or the current average consensus of value.
By using a longer-term trend-following indicator, perhaps a weekly MACD histogram, traders can identify the direction of the longer-term trend. Bull power and bear power are then used to find trades on the daily charts that move in the same direction as the weekly trend. The triple screen earns its "screening" label because it eliminates all signals but those in the direction of the trend: if the weekly trend is up, only buy signals are returned from Elder-Ray. If the weekly trend is down, only Elder-Ray sell signals are considered.
There are two absolutely essential conditions that need to be in place for traders to consider buying: 1) the weekly trend should be up, and 2) bear power, as represented on Elder-Ray, should be negative but rising. The second condition - negative bear power - is worth exploring. The opposite condition, in which bear power is positive, occurs in a runaway uptrend, a dangerous market environment for trading, despite the apparent strength of the trend. The problem with buying in a runaway uptrend is that you are betting on the greater fool theory, which states that your profit will be realized only by eventually selling to somebody willing to pay an even higher price.
When bear power is negative but rising, bears are showing a bit of strength but are beginning to slip once again. By placing a buy order above the high of the last two days, your stop order will be filled only if the rally continues. Once you have gone long, you can protect your position with a stop below the latest minor low.
Bullish divergences between bear power and price (average consensus of value) represent the strongest buy signals. If prices fall to a new low but bear power shows a higher bottom, prices are falling and bears become weaker. When bear power moves up from this second bottom, you can comfortably buy a larger number of shares than you typically would in your usual position.
You can also use Elder-Ray to determine the best time to sell your position. By tracking the pattern of peaks and valleys in bull power, you can ascertain the power of bulls. By stacking the peaks in actual price against the peaks in bull power, you can determine the strength of the uptrend - if every new peak in price comes along with a new peak in bull power, the uptrend is safe. When prices reach a new high but bull power reaches a lower peak than that of its previous rally, the bulls are losing their power and a sell signal is issued.
Elder-Ray as the second screen in the triple screen trading system can also be used to determine the conditions in which shorting is appropriate. The two essential conditions for shorting are, firstly, that the trend is down and, secondly, that bull power is positive but falling.
If bull power is already negative, selling short is inappropriate because bears have control over the market bulls. If you short sell in this condition, you are effectively betting that bears have sufficient strength to push bulls even farther under water. Furthermore, as in the case discussed above, wherein the trader holds a long position during positive bear power, you are betting on the greater fool theory.
When bull power is positive but falling, the bulls have managed to grasp a bit of strength but are beginning to sink once again. If you place a short order below the low of the last two days, you receive an order execution only if the decline continues. You can then place a protective stop above the latest minor high.
Bearish divergences between bull power and prices (average consensus of value) give the strongest shorting signals. If prices hit a new high but bull power hits a lower top, the bulls are weaker than before, and the uptrend may not continue. When bull power inches down from a lower top, you can safely sell short a larger-than-usual position.
You can also determine when to cover your short positions on the basis of a reading of Elder-Ray. When your longer-term trend is down, bear power will indicate whether bears are becoming stronger or weaker. If a new low in price occurs simultaneously with a new low in bear power, the current downtrend is relatively secure.
A bullish divergence issues a signal to cover your shorts and prepare to enter into a long position. Bullish divergences occur when prices hit a new low and bear power hits an even shallower bottom, when bears are losing their momentum and prices are falling slowly.
For both long and short positions, divergences among bull power, bear power and prices indicate the best trading opportunities. In the context of the long-term trend indicated by our first market screen, Elder-Ray identifies the moment when the market's dominant group falters below the surface of the trend.