# Rate of Change / Momentum Indicator

The Rate of Change (or Momentum) Oscillator is a simple but effective tool for measuring and analyzing the price momentum and trend direction of a market

8 minutes

#### Introduction

J. Welles Wilder Jr., a well-known technical analyst and trader, introduced the Rate of Change (ROC) indicator in his book “New Concepts in Technical Trading Systems” in 1978. Wilder is a renowned creator of several other popular technical indicators such as the Relative Strength Index (RSI) and the Average True Range (ATR).

The ROC is a technical indicator that measures the percentage change in the price of a financial instrument over a specified period, indicating the speed of price change. This indicator can be helpful in identifying trends and potential trend reversals. To calculate ROC, the current price is divided by the price “n” periods ago and then multiplied by 100 to convert it into a percentage. Traders often use ROC in combination with other technical indicators to confirm or identify potential trading opportunities.

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#### Computing the ROC Indicator

The Rate of Change (ROC) indicator is a popular technical analysis tool that calculates the percentage change in price between the current price and the price from a chosen number of periods ago. The formula to calculate the ROC is straightforward:

ROC = [(Current Price - Price n periods ago) / Price n periods ago] x 100

where: “n” is the number of periods chosen, such as 12 or 26.

To compute the ROC, traders need to choose the number of periods they want to use, subtract the price from n periods ago from the current price, and divide the difference by the price from n periods ago. The resulting value is then multiplied by 100 to obtain the percentage change, which is the ROC for that period. This process is repeated for each period to create a ROC line that traders can use to spot trends and potential reversal points.

The ROC line is usually plotted as a line chart that oscillates around a zero line, which represents the level where the price hasn’t changed from the previous period. Positive values above the zero line indicate that the price has increased by a certain percentage, while negative values below the zero line indicate that the price has decreased by a certain percentage. The ROC line’s appearance can be customized, such as by changing its color, thickness, and style. In some charting software, traders can also choose to plot the ROC line as a histogram or a bar chart.

#### Using the ROC / Momentum Indicator in trading

The ROC oscillator is a trading tool that can provide insight into the momentum and trend direction of a market. There are several ways to use the ROC oscillator in trading:

Momentum strength and direction

The ROC oscillator can indicate the strength and direction of price momentum. A positive ROC value shows that the current price is higher than the previous price, which indicates an uptrend. A negative ROC value indicates that the current price is lower than the previous price, indicating a downtrend. The higher or lower the ROC value, the stronger or weaker the momentum.

Crossovers

The ROC oscillator can be plotted as a line or histogram on a chart, typically below the price action. The oscillator has a zero line that serves as a center point. When the ROC oscillator is above zero, it means that the current price is higher than the price n periods ago, indicating positive momentum and an uptrend. When the ROC oscillator is below zero, it means that the current price is lower than the price n periods ago, indicating negative momentum and a downtrend.

Crossovers and divergences can also generate buy and sell signals. A crossover occurs when the ROC oscillator crosses above or below a zero line or signal line. A zero line crossover indicates a change in trend direction, while a signal line crossover indicates a change in trend strength. The signal line is usually a moving average of the ROC oscillator, such as a 9-period exponential moving average (EMA). A buy signal is generated when the ROC oscillator crosses above zero or above the signal line, while a sell signal is generated when the ROC oscillator crosses below zero or below the signal line.

Overbought and oversold conditions

The ROC oscillator can identify overbought and oversold conditions in a market. Overbought conditions occur when the ROC oscillator reaches an extreme high value, indicating that the market has risen too fast and a pullback or correction may be due. Oversold conditions occur when the ROC oscillator reaches an extreme low value, indicating that the market has fallen too fast and a bounce or recovery may be due.

Divergence

Divergence occurs when the ROC oscillator moves in the opposite direction of the price action, indicating a weakening of the trend and a potential reversal. A bullish divergence occurs when the price makes lower lows while the ROC oscillator makes higher lows, indicating that selling pressure is decreasing and the downtrend may be losing steam. A bearish divergence occurs when the price makes higher highs while the ROC oscillator makes lower highs, indicating that buying pressure is decreasing and the uptrend may be losing steam.

Combination with other indicators

The ROC oscillator can be combined with other technical indicators and tools to confirm and enhance its signals. Trend lines, support and resistance levels, moving averages, or other oscillators can be used to identify the trend direction and strength, as well as potential entry and exit points for trades. Different time frames can also provide a broader or narrower perspective of the market.

Although the ROC oscillator is a useful indicator, it is not foolproof and should not be used in isolation. Traders should always use their own judgment and analysis before making any trading decisions.

#### Advantages & Limitations of ROC / Momentum Indicator

Here are some advantages and limitations of using the Rate of Change or Momentum Indicator in trading:

• The ROC indicator is a straightforward tool for measuring price momentum in a market.
• ROC can assist traders in identifying overbought and oversold conditions, which can aid in the timing of entry and exit points in a trade.
• ROC can be used in conjunction with other technical analysis tools to verify trends and possible reversals.
• The ROC oscillator is versatile and can be customized to fit the preferences and needs of individual traders.
• ROC can be applied to a broad range of financial instruments, including stocks, commodities, currencies, and indices.

Limitations

• ROC is a lagging indicator, and it may not generate timely signals for entering or exiting trades.
• ROC can produce false signals in choppy or sideways markets, which can result in losses if acted upon.
• Sudden price spikes or gaps can distort the readings of ROC, making it less dependable.
• ROC may not work well in markets that are heavily influenced by news or events that are unpredictable.
• The effectiveness of ROC can differ depending on the time frame used, and traders may need to experiment with various settings to find the most appropriate one for their trading style.

The ROC indicator is a versatile tool that can be used to gauge the momentum and trend direction of a market, as well as potential reversal points and overbought and oversold conditions. With its straightforward calculation and customizable settings, ROC can be applied to a wide range of financial instruments and can be used in conjunction with other technical analysis tools to confirm trends and potential reversals. Traders who use ROC in combination with their own judgment and analysis can gain a better understanding of market movements and make informed trading decisions.

However, it’s important to note that ROC is not a foolproof indicator and may not always provide timely or accurate signals for entering or exiting trades. Traders should be aware of the limitations of ROC, such as its lagging nature, potential for false signals in choppy or sideways markets, and susceptibility to sudden price spikes or gaps. The effectiveness of ROC can also vary depending on the time frame used, and traders may need to experiment with different settings to find the most suitable one for their trading style. As with any trading tool or strategy, traders should always use caution and exercise their own judgment and analysis before making any trading decisions.

For examples of customizable Rate of Change (RoC) a.k.a. Momentum indicator factory scans that can be edited, modified, or revised, and subsequently scanned through ChartAlert’s native stock screener or technical analysis scanner, click here.