You know which metrics you want to show on your dashboard, and many of them are actually a series of values – for example, the total monthly expenses for the six departments in your organization for the last 12 months.
You could just show tables of numbers but generally charts and graphs work much better because:
- They are compact: More information can be presented in a smaller area, making them particularly useful in dashboards.
- They are easy to scan quickly. Imagine trying to make sense of numbers in a 52-cell table representing total sales for the last 52 weeks. Then imagine how much easier it is to scan, say, a bar graph that presents the same information.
- They make it easier to see patterns. In the above example, unless you are a math savant seeing patterns in numbers versus a chart is much more difficult.
But there are two caveats:
- Levels of precision vary. A graph will never show values as precisely as a table of numbers, so if precision is paramount then having a table with a graph, or a table on its own might be necessary. Also some types of graphs allow users to “eyeball” the individual values they contain much more precisely than other types.
- Users have to know how to read them. Knowledge levels can vary among audiences, and it may be worthwhile testing some types of graphs with your users to make sure they are comfortable with them.
Not all graphs and charts work on dashboard
With the tables versus graph question answered your next decision is what type of chart of graph.
This is a really important question because not all graphs and chart types work well in a dashboard and some work well for some data but not other.
So it pays to understand what information you want to convey, and choose a chart or graphic that is suited to the task.
Here’s how some common graph types stack up:
Here are some chart types that experts agree (most anyway) never work well on dashboards because data can always be represented in a more scannable, clear, precise and familiar way with one of the above charts:
- Radar graphs
- Bubble charts
- Anything with a third axis (surface graphs, 3D line graphs, 3D bar graphs, etc.)
Again, they may work well for Infographics, reports or in-depth analysis just not dashboards.
Have a chart you love to use on dashboards? Disagree with any of the recommendations? Would love to hear from you.
Next in this series: Common dashboard design mistake #5: the misuse of colour.