A:

The interpretation of a stock chart can vary among different traders depending on the type of price scale used when viewing the data. As this question suggests, the two most common types of price scales are 1) logarithmic (also referred to as log) and 2) linear (also referred to as arithmetic).

A linear price scale is plotted on the side of the chart so that there is an equal distance between the prices, and each unit change on the chart is represented by the same vertical distance on the scale, regardless of what price level the asset is at when the change occurs. By contrast, a logarithmic price scale is plotted so that the prices in the scale are not positioned equidistantly; instead, the scale is plotted in such a way that two equal percent changes are plotted as the same vertical distance on the scale.

logvslinear.gif

As you can see from the charts above, an increase in price from $10 to $15 is the same as an increase from $20 to $25 on the linear chart because both scenarios represent an increase of $5. However, a logarithmic price scale will show the vertical distance between $10 and $15 to be different than the $5 distance between $20 to $25. The reason for this is that a change of $5 (when the price is at $10) represents a 50% increase, while a move from $20 to $25 is a 25% increase. Since a 50% increase is more significant than 25%, chartists will use a larger distance between the prices to clearly show the magnitude of the changes. When using a logarithmic scale, the vertical distance between the prices in the scale will be equal when the percent change between the values is the same. Using the above example, the distance between $10 and $15 would be equal to the distance between $20 and $30 because they both represent a price increase of 50%. In general, most traders and charting programs use the logarithmic scale, but it is always a good idea to explore other approaches to determine which is the most suitable for your trading style.

To learn more, see our Technical Analysis Tutorial.

RELATED FAQS
  1. What is Fibonacci retracement, and where do the ratios that are used come from?

    Fibonacci retracement is a very popular tool among technical traders and is based on the key numbers identified by mathematician ... Read Full Answer >>
  2. What are some of the most common technical indicators that back up Doji patterns?

    The doji candlestick is important enough that Steve Nison devotes an entire chapter to it in his definitive work on candlestick ... Read Full Answer >>
  3. Tame Panic Selling with the Exhausted Selling Model

    The exhausted selling model is a pricing strategy used to identify and trade based off of the price floor of a security. ... Read Full Answer >>
  4. Point and Figure Charting Using Count Analysis

    Count analysis is a means of interpreting point and figure charts to measure vertical price movements. Technical analysts ... Read Full Answer >>
  5. What assumptions are made when conducting a t-test?

    The common assumptions made when doing a t-test include those regarding the scale of measurement, random sampling, normality ... Read Full Answer >>
  6. How are double exponential moving averages applied in technical analysis?

    Double exponential moving averages (DEMAS) are commonly used in technical analysis like any other moving average indicator ... Read Full Answer >>
Related Articles
  1. Investing Basics

    Free Cash Flow Yield: A Fundamental Indicator

    Free cash flow can measure a business’s performance as if you’re looking at its net income line.
  2. Technical Indicators

    Four Commonly Used Indicators In Trend Trading

    No single indicator can punch a ticket to market riches, but here are four that remain popular among trend traders.
  3. Active Trading Fundamentals

    4 Stocks With Bullish Head and Shoulders Patterns for 2016 (PG, ETR)

    Discover analyses of the top four stocks with bullish head and shoulders patterns forming in 2016, and learn the prices at which they should be considered.
  4. Chart Advisor

    Uptrending Stocks Dwindle, a Few Remain (EW, WEC, WR)

    The number of uptrending stocks is shrinking, but here a few that remain in uptrends.
  5. Chart Advisor

    Trade Setups Based on Descending Trend Channels (LBTYK, RRC)

    These descending trend channels have provided reliable sell signals in the past, and are giving the signal again.
  6. Investing News

    Is It Time To Sell Technology Stocks? (LNKD, AAPL)

    Technology stocks have taken a drubbing in recent days. Is it time to sell them?
  7. Chart Advisor

    How Are You Trading The Breakdown In Growth Stocks? (VOOG, IWF)

    Based on the charts of these two ETFs, bearish traders will start turning their attention to growth stocks.
  8. Chart Advisor

    Breakout Opportunity Stocks: CPA, GNRC, WWE

    After a period of contracting volatility, watch for breakouts and bigger moves to come in these stocks.
  9. Charts & Patterns

    How To Use Volume To Improve Your Trading

    The basic guidelines to analyzing volume may not apply in all situations, but overall, they can help direct entry and exit decisions.
  10. Trading Strategies

    4 Common Active Trading Strategies

    Active trading entails buying and selling securities with the intent of profiting from short-term price movements.
RELATED TERMS
  1. Golden Cross

    A crossover involving a security's short-term moving average ...
  2. Cup and Handle

    A pattern on bar charts resembling a cup with a handle. The cup ...
  3. Dead Cat Bounce

    A temporary recovery from a prolonged decline or bear market, ...
  4. Confirmation

    The use of an additional indicator or indicators to substantiate ...
  5. Fintech

    Fintech is a portmanteau of financial technology that describes ...
  6. Indicator

    Indicators are statistics used to measure current conditions ...
Hot Definitions
  1. Harry Potter Stock Index

    A collection of stocks from companies related to the "Harry Potter" series franchise. Created by StockPickr, this index seeks ...
  2. Liquidation Margin

    Liquidation margin refers to the value of all of the equity positions in a margin account. If an investor or trader holds ...
  3. Black Swan

    An event or occurrence that deviates beyond what is normally expected of a situation and that would be extremely difficult ...
  4. Inverted Yield Curve

    An interest rate environment in which long-term debt instruments have a lower yield than short-term debt instruments of the ...
  5. Socially Responsible Investment - SRI

    An investment that is considered socially responsible because of the nature of the business the company conducts. Common ...
Trading Center