What is Force Index indicator, the instructions of Force Index and how to use the Force Index indicator, the calculation of Force Index indicator and the Force Index indicator main parameters
The Force Index is an indicator that uses price and volume to assess the power behind a move or identify possible turning points. Developed by Alexander Elder, the Force Index was introduced in his classic book, Trading for a Living. According to Elder, there are three essential elements to a stock’s price movement: direction, extent and volume. The Force Index combines all three as an oscillator that fluctuates in positive and negative territory as the balance of power shifts. The Force Index can be used to reinforce the overall trend, identify playable corrections or foreshadow reversals with divergences.
This index measures the Bulls Power at each increase, and the Bulls Power at each decrease. It connects the basic elements of market information: price trend, its drops, and volumes of transactions. This index can be used as it is, but it is better to approximate it with the help of Moving Average. Approximation with the help a short moving average (the author proposes to use 2 intervals) contributes to finding the best opportunity to open and close positions. If the approximations is made with long moving average (period 13), the index shows the trends and their changes.
- It is better to buy when the forces become minus (fall below zero) in the period of indicator increasing tendency;
- The force index signalizes the continuation of the increasing tendency when it increases to the new peak;
- The signal to sell comes when the index becomes positive during the decreasing tendency;
- The force index signalizes the Bears Power and continuation of the decreasing tendency when the index falls to the new trough;
- If price changes do not correlate to the corresponding changes in volume, the force indicator stays on one level, which tells you the trend is going to change soon.
The force of every market movement is characterized by its direction, scale and volume. If the closing price of the current bar is higher than the preceding bar, the force is positive. If the current closing price if lower than the preceding one, the force is negative. The greater the difference in prices is, the greater the force is. The greater the transaction volume is, the greater the force is.
FORCE INDEX (i) = VOLUME (i) * ((MA (ApPRICE, N, i) - MA (ApPRICE, N, i-1))
- FORCE INDEX (i) — Force Index of the current bar;
- VOLUME (i) — volume of the current bar;
- MA (ApPRICE, N, i) — any Moving Average of the current bar for N period: Simple, Exponential, Weighted or Smoothed;
- ApPRICE — applied price;
- N — period of the smoothing;
- MA (ApPRICE, N, i-1) — any Moving Average of the previous bar.
As noted above, there are three elements to the Force Index. First, there is either a positive or negative price change. A positive price change signals that buyers were stronger than sellers, while a negative price change signals that sellers were stronger than buyers. Second, there is the extent of the price change, which is simply the current close less the prior close. The "extent" shows us just how far prices moved. A big advance shows strong buying pressure, while a big decline shows strong selling pressure. The third and final element is volume, which, according to Elder, measures commitment. Just how committed are the buyers and sellers? A big advance on heavy volume shows a strong commitment from buyers. Likewise, a big decline on heavy volume shows a strong commitment from sellers. The Force Index quantifies these three elements into one indicator that measures buying and selling pressure.
The Force Index can be used to reinforce or determine the trend. The trend in question, short-term, medium-term or long-term, depends on the Force Index parameters. While the default Force Index parameter is 13, chartists can use a higher number for more smoothing or a lower number for less smoothing. The chart below shows Home Depot with a 100-day Force Index and a 13-day Force Index. Notice how the 13-day Force Index is more volatile and jagged. The 100-day Force Index is smoother and crosses the zero line fewer times. In this regard, the 100-day Force Index can be used to determine the medium or long-term trend. Notice how a resistance breakout on the price chart corresponds to a resistance breakout on the 100-day Force Index. The 100-day Force Index moved into positive territory and broke resistance in mid February. The indicator remained positive during the entire uptrend and turned negative in mid May. The early June support break on the price chart was confirmed with a support break in the Force Index.
Bullish and bearish divergence can alert chartists of a potential trend change. Divergences are classic signals associate with oscillators. A bullish divergence forms when the indicator moves higher as the security moves lower. The indicator is not confirming weakness in price and this can foreshadow a bullish trend reversal. A bearish divergence forms when the indicator moves lower as the security moves higher. Even though the security is moving higher, the indicator shows underlying weakness by moving lower. This discrepancy can foreshadow a bearish trend reversal.
Confirmation is an important part of bullish and bearish divergences. Even though the divergences signal something is amiss, confirmation from the indicator or price chart is needed. A bullish divergence can be confirmed with the Force Index moving into positive territory or a resistance breakout on the price chart. A bearish divergence can be confirmed with the Force Index moving into negative territory or a support break on the price chart. Chartists can also use candlesticks, moving average crosses, pattern breaks and other forms of technical analysis for confirmation.
The chart above shows Best Buy (BBY) with the Force Index (39) sporting a series of divergences. The green lines show bullish divergences, while the red lines show bearish divergences. A bullish divergence is confirmed when the Force Index (39) crosses into positive territory (green dotted lines). A bearish divergence is confirmed when the Force Index (39) crosses into negative territory (red dotted lines). Chartists can also use trendline breaks on the price chart for confirmation.
This chart shows two versions of the Force Index. The Force Index (13) captures short-term fluctuations and is more sensitive. The Force Index (39) captures medium-term fluctuations and is smoother. The 39-day Force Index produces fewer zero line crossovers and these crossovers last longer. There is no right or wrong answer for these settings. It depends on trading objectives, time horizon and analytical style.
The Force Index can be used in conjunction with a trend following indicator to identify short-term corrections within that trend. A pullback from overbought levels represents a short-term correction within an uptrend. An oversold bounce represents a short-term correction within a downtrend. Yes, corrections can be up or down, it depends on the direction of the bigger trend. Alexander Elder recommends using a 22-day EMA for trend identification and a 2-day Force Index to identify corrections. The trend is up when the 22-day EMA is moving higher, which means the 2-day Force Index would be used to identify short-term pullbacks for buying. The trend is down when the 22-day EMA is moving lower, which means the 2-day Force Index would be used to identify short-term bounces for selling. This is an aggressive strategy best suiting for active traders. The timeframe can be adjusted by using a longer moving average and timeframe for the Force Index. For example, medium-term traders might experiment with a 100-day EMA and 10-day Force Index.
There are two-schools of thought regarding the correction play. Traders can either act as soon as the correction is evident or act when there is evidence the correction has ended. Let’s look at an example with the 22-day EMA and 2-day Force Index. Keep in mind that this is designed to identify very short corrections within a bigger trend. The chart below shows Texas Instruments (TXN) with the 22-day EMA turning up in mid September.
With the 22-day EMA rising, traders are looking for very short-term pullbacks when the 2-day Force Index turns negative. Traders can act when the Force Index turns negative or wait for it to move back into positive territory. Acting when negative may improve the reward-to-risk ratio, but the correction could extend a few more days. Waiting for the Force Index to turn positive again shows some strength that could signal the correction has ended. The green dotted lines show when the 2-day Force Index turns negative.
The Force Index is uses both price and volume to measure buying and selling pressure. The price portion covers the trend, while the volume portion determines the intensity. At its most basic, chartists can use a long-term Force Index to confirm the underlying trend. The bulls have the edge when the 100-day Force Index is positive. The bears have the edge when the 100-day Force Index is negative. Armed with this information, traders can then look for short-term setups in harmony with the larger trend, such as bullish setups in a larger uptrend or bearish setups within a larger downtrend. As with all indicators, traders should use the Force Index in conjunction with other indicators and analysis techniques.
- Period: Averaging period for calculation, default is 13
- MA method:
- Linear weighted
- Apply to: Applied price
- Median Price, (high+low)/2
- Typical Price, (high+low+close)/3
- Weighted Close, (high+low+close+close)/4