•Use it when an item is repeatedly measured, to show changes across time.
•Use it when measuring several different items which can be shown on the same scale, to show how they change relative to one another.
•Use it when measuring progress towards a goal, to show the relative improvement.
•Use it, rather than a Bar Chart, to show continuous change, rather than discrete measurements. It is also better when there are many measurements.
•Use it, rather than a Control Chart, when not measuring the degree of control of a process.