The Parabolic Stop and Reverse (SAR) Indicator in Technical Analysis
The Parabolic Stop and Reverse (SAR) indicator is a technical analysis tool used for identifying market trends and possible reversal points. It was developed by J. Welles Wilder Jr. in the late 1970s and presented in his book New Concepts in Technical Trading Systems. The book included other commonly used indicators like the Relative Strength Index (RSI). Wilder referred to his approach as the Parabolic Time/Price System, and he defined SAR as the point at which a Long trade is exited and a Short trade is entered, or vice versa. The SAR indicator is now commonly known as the Parabolic SAR indicator. Wilder manually developed several technical analysis indicators, but they have now been automated in most digital trading systems and charting software. This automation has made these techniques easy to use and no longer require manual calculations.
How Does The Parabolic SAR Indicator Work?
The Parabolic SAR indicator is a graphical tool that involves small dots placed above or below the market price, creating a parabola with each dot representing a single SAR value. During an uptrend, the dots are plotted below the price, while they are plotted above it during a downtrend. During periods of consolidation where the market moves sideways, the dots are also plotted but will change sides more frequently. However, during non-trending markets, the Parabolic SAR indicator is less useful.
The Parabolic SAR indicator offers investors several advantages, including insights into market trends, potential reversal points, and trend duration, thereby increasing the chances of identifying good buying and selling opportunities.
Traders also use the Parabolic SAR indicator to determine dynamic stop-loss prices, a technique known as trailing stop-loss. This technique enables traders to lock in profits by closing positions as soon as the trend reverses. In some situations, it may also prevent traders from closing profitable positions or entering trades too early.
The Parabolic SAR is most useful in trending markets but not so much helping during periods of consolidation, which may cause significant losses due to false signals.
The sensitivity of the indicator can be adjusted manually, but a higher sensitivity increases the likelihood of false signals. False signals can encourage traders to close winning positions too early or give investors a false sense of optimism, inducing them to buy too soon.
Furthermore, because the Parabolic SAR does not consider trading volume, it does not provide much information about the strength of a trend. Therefore, it is important to use additional strategies or indicators, such as the Average Directional Index or moving averages, to offset the limitations of the Parabolic SAR. Wilder recommended using the Average Directional Index and the Parabolic SAR together to gauge the strength of trends. The RSI indicator can also be included in the analysis before entering a position.
The Parabolic SAR Calculation
The Parabolic SAR calculation is now automated by computer programs. To calculate it manually, you will need to gather several components, which are explained below.
The Parabolic SAR uses the previous day's SAR to calculate today's SAR and today's SAR to calculate tomorrow's SAR. During uptrends, the SAR value is based on previous highs, while during downtrends, previous lows are used. Extreme Points (EP) refer to a trend's highest and lowest points.
SAR = Prior SAR + AF x (Prior EP – Prior SAR)
SAR = Prior SAR – AF x (Prior SAR – Prior EP)
An acceleration factor (AF) of 0.02 is used initially, increasing by 0.02 whenever there is a new high or low. If the limit of 0.20 is reached, it is maintained for the duration of that trend. Traders can adjust the AF manually to increase or decrease the indicator's sensitivity, but Wilder recommended using an AF of 0.02. Wilder also suggested calculating the first SAR value based on the last EP before a trend reversal. Traders can find this EP by going back on their chart until a clear reversal is found. The local bottom for that correction can be used as the first SAR value for the following uptrend.
The Parabolic SAR has been around since the 1970s, but it is still commonly used across many investment options such as stocks, commodities, cryptocurrencies, and Forex. However, no market analysis tool can ensure 100% accuracy, and investors should be aware of this fact before utilizing the Parabolic SAR or any other strategy. Proper knowledge of financial markets and technical analysis is necessary, as well as implementing appropriate trading and risk management strategies to offset the inherent risks.