The principles of market psychology underlie every technical indicator, so a good understanding of crowd behavior is crucial to your comprehension of the fundamentals of certain technical indicators. The psychology of the market is hard to predict, but there are several trusted indicators that make it easier for investors to postulate on directional changes.
The moving average convergence divergence (MACD) is simply a tool that measures shifts in consensus from bullishness to bearishness, and vice versa. Extending the basic MACD to a deeper level, we find the MACD-histogram, which is actually a tool for determining the difference between long-term and short-term consensus of value. The measure tracks the difference between the fast MACD line (short-term consensus) and the slow signal line (longer-term consensus).
The Directional System
The directional system was developed by J. Welles Wilder, Jr., as a means of identifying trends that are strong enough to be valid and useful indicators for traders. Directional lines are constructed to determine whether trends are bullish or bearish: When a positive directional line is above the negative line, bullish traders possess greater strength (and a bullish signal is given). The opposite situation indicates bearishness. More telling is the average directional indicator (ADX), which rises when the spread between the positive and negative lines increases. When the ADX rises, profitable investments are getting ever stronger, and losers are getting weaker; furthermore, the trend is likely to continue.
Momentum and Rate of Change (RoC)
Momentum indicators measure changes in mass optimism or pessimism by comparing today's consensus of value (price) to an earlier consensus of value. Momentum and RoC are specific measures against which actual prices are compared: When prices rise but momentum or rate of change falls, a top is likely near. If prices reach a new high but momentum or RoC reach a lower top, a sell signal is realized. These rules also apply in the opposite situation, when prices fall or new lows are reached.
Smoothed Rate of Change
The smoothed rate of change compares today's exponential moving average (average consensus) to the average consensus of some point in the past. The smoothed rate of change is simply an enhanced version of the RoC momentum indicator—it is intended to alleviate the RoC's potential for errors in determining the market's attitude of bullishness or bearishness.
Williams %R (Wm%R)
Wm%R, a measure focusing on closing prices, compares each day's closing price with a recent consensus range of value (range of closing prices). If on a particular day, bulls are able to push the market to the top of its recent range, Wm%R issues a bullish signal, and a bearish signal is issued if bears are able to push the market to the bottom of its range.
Similar to Wm%R, stochastics measure closing prices against a range. If bulls push prices up during the day but cannot achieve a close near the top of the range, stochastic turns down, and a sell signal is issued. The same also holds true if bears push prices down but cannot achieve a close near the low, in which case a buy signal is issued.
Relative Strength Index (RSI)
RSI also measures market psychology in a fundamentally similar way to that of Wm%R. RSI is almost always measured with a computer, typically over a seven- or nine-day range, producing a numerical result between 0 and 100 that points to oversold or overbought situations; the RSI, therefore, gives a bullish or bearish signal, respectively.
The total volume of shares traded is an excellent way in which to ascertain the psychology of the market. Volume is actually a measure of investors' emotional state: While a burst of volume will cause sudden pain to poorly timed investments and immediate elation for those who made wise investments, low volume will likely not result in a significant emotional response.
The longest lasting trends generally occur when emotion is the lowest. When volume is moderate and both shorts and longs do not experience the roller coaster ride of emotion, the trend can reasonably be expected to continue until the emotion of the market changes. In a longer-term trend such as this, small price changes either up or down do not precipitate much emotion, and even a series of small changes occurring day after day (enough to create a major, gradual trend) will generally not generate severe emotional reactions.
In the case of short selling, a market rally may serve to flush out those individuals holding short positions, causing them to cover and subsequently push the market higher. The same principle holds true on the flip side: when the longs give up and bailout, the decline pulls more poorly timed investments with it. At the most fundamental level of market volume, both short and long investors who lose money, who collectively exit their positions, are the primary drivers behind significant volume trends.