Technical analysis is built on the assumption that prices trend. Trend Lines are an important tool in technical analysis for both trend identification and confirmation. A trend line is a straight line that connects two or more price points and then extends into the future to act as a line of support or resistance. Many of the principles applicable to support and resistance levels can be applied to trend lines as well. It is important that you understand all of the concepts presented in our Support and Resistance article before you continue.
Definition
Uptrend Line
An uptrend line has a positive slope and is formed by connecting two or more low points. The second low must be higher than the first for the line to have a positive slope. Uptrend lines act as support and indicate that net-demand (demand less supply) is increasing even as the price rises. A rising price combined with increasing demand is very bullish, and shows a strong determination on the part of the buyers. As long as prices remain above the trend line, the uptrend is considered solid and intact. A break below the uptrend line indicates that net-demand has weakened and a change in trend could be imminent
Downtrend Line
A downtrend line has a negative slope and is formed by connecting two or more high points. The second high must be lower than the first for the line to have a negative slope. Downtrend lines act as resistance, and indicate that net-supply (supply less demand) is increasing even as the price declines. A declining price combined with increasing supply is very bearish, and shows the strong resolve of the sellers. As long as prices remain below the downtrend line, the downtrend is solid and intact. A break above the downtrend line indicates that net-supply is decreasing and that a change of trend could be imminent.
Scale Settings
High points and low points appear to line up better for trend lines when prices are displayed using a semi-log scale. This is especially true when long-term trend lines are being drawn or when there is a large change in price. Most charting programs allow users to set the scale as arithmetic or semi-log. An arithmetic scale displays incremental values (5,10,15,20,25,30) evenly as they move up the y-axis. A $10 movement in price will look the same from $10 to $20 or from $100 to $110. A semi-log scale displays incremental values in percentage terms as they move up the y-axis. A move from $10 to $20 is a 100% gain, and would appear to be a much larger than a move from $100 to $110, which is only a 10% gain.
Validation
It takes two or more points to draw a trend line The more points used to draw the trend line, the more validity attached to the support or resistance level represented by the trend line. It can sometimes be difficult to find more than 2 points from which to construct a trend line Even though trend lines are an important aspect of technical analysis, it is not always possible to draw trend lines on every price chart. Sometimes the lows or highs just don’t match up, and it is best not to force the issue. The general rule in technical analysis is that it takes two points to draw a trend line and the third point confirms the validity.
Spacing of Points
The lows used to form an uptrend line and the highs used to form a downtrend line should not be too far apart, or too close together. The most suitable distance apart will depend on the time frame, the degree of price movement, and personal preferences. If the lows (highs) are too close together, the validity of the reaction low (high) may be in question. If the lows are too far apart, the relationship between the two points could be suspect. An ideal trend line is made up of relatively evenly spaced lows (or highs). The trend line in the above MSFT example represents well-spaced low points.
Angles
As the steepness of a trend line increases, the validity of the support or resistance level decreases. A steep trend line results from a sharp advance (or decline) over a brief period of time. The angle of a trend line created from such sharp moves is unlikely to offer a meaningful support or resistance level. Even if the trend line is formed with three seemingly valid points, attempting to play a trend line break or to use the support and resistance level established it will often prove difficult.
The trend line for Yahoo! (YHOO)[Yhoo] was touched four times over a 5-month period. The spacing between the points appears OK, but the steepness of the trend line is unsustainable, and the price is more likely than not to drop below the trend line. However, trying to time this drop or make a play after the trend line is broken is a difficult task. The amount of data displayed and the size of the chart can also affect the angle of a trend line. Short and wide charts are less likely to have steep trend lines than long and narrow charts. Keep that in mind when assessing the validity and sustainability of a trend line.
Internal Trend Lines
Sometimes there appears to be the possibility for drawing a trend line, but the exact points do not match up cleanly. The highs or lows might be out of whack, the angle might be too steep or the points might be too close together. If one or two points could be ignored, then a fitted trend line could be formed. With the volatility present in the market, prices can over-react, and produce spikes that distort the highs and lows. One method for dealing with over-reactions is to draw internal trend lines. Even though an internal trend line ignores price spikes, the ignoring should be within reason.
Sometimes, there is a price cluster with a high or low spike sticking out. A price cluster is an area where prices are grouped within a tight range over a period of time. The price cluster can be used to draw the trend line, and the spike can be ignored.
interest in intraday