Percent change

What the numbers mean

The only setting is the window: change is measured from the first bar of the chosen period to the latest price, expressed as a percentage.

• The selected period — day, week, month, year to date
• Measured from the first bar of that window to the latest price
• Percentage form is what makes different share prices comparable

How it is used

The plainest comparison tool there is — used to line up several securities on the same scale so relative performance is visible regardless of share price.

• Lining up several securities on one scale for relative performance
• Reading a quote page's daily change without reference to the share price

How it relates to everything else

This is the simplest form of the same idea Rate of Change plots continuously. Its weakness is also the simplest: the answer depends entirely on the start date, which makes it the easiest number on a chart to present misleadingly.

• ROC is this measured on a rolling basis
• Start-date sensitivity is its main flaw
• Use log scaling on charts when comparing long periods

What to watch for

The answer depends entirely on the start date chosen, which makes it the easiest statistic on a chart to present misleadingly.