When I think about the line graphs the first picture that comes to mind is the hospital. The vitals, and specifically heart function, is measured by a line graph moving across a 1-2 second time frame. It makes for a quick representation to the caretakers of what the trending health is for the patient. In the same respect, this is the strength of the line graph; trending visualization.
For example, you may have seen a line graph that shows the average time to response on a day-over-day basis over a period of time. Days run from left to right across the horizontal (x) axis and minutes run bottom to top along the vertical (y) axis. Data points (in this case, the time it takes to respond to a ticket request) are plotted and then the dots connected.
Line graph usage makes sense for this kind of data for several reasons:
It’s easy to spot general trends over time, such as an ongoing increase or decrease in the resolution time;
It’s easy to spot anomalies that might bear a closer look, such as a significant increase in response to ticket time during a month where times are improving;
It’s easy to locate specific information, such as the day of the week in which the lag time was the highest; and
If there is a recognizable trend, it is possible to extrapolate values not covered in the graph.
Another advantage of a line graph is that it is easy to clearly represent multiple data sets for comparison. For example, if we wanted to compare the daily ticket response time with the number of engineers working in the NOC, this could be accomplished by simply plotting a second line. Different data sets are typically represented by visually different lines: either different colors or one solid line and one dashed, for example.
Of course, that’s just one illustration. A line graph can be used in the same way to show the relationship between any two variables: Sales versus pending sales pipeline, for instance, or average time to resolution versus ticket count which you can see in the image below from one of our gauges.
The power of grasping trending information with a quick look at a line graph is very beneficial to a business owner or employee. It lets you forecast where assets need to be deployed in the future. Being able to do so will turn a typical business weakness into a strength that will leave competitors behind.