This is the seventh in a series of tips on different chart types. The idea is to fill up your toolbox with various types of charts for making sense of data. This week, I give you the pictogram chart.
Active Ingredients (What is a pictogram chart?)
Pictogram charts use icons instead of bars or circles, usually to show how many units are in a group. Probably the most common icon is the stick figure used to represent a person or a group of people (e.g. each stick figure represents 100 people.)
Uses
Pictogram charts can be useful when bars or circles just seem too abstract, and you want to emphasize that you are talking about people, animals, apartment buildings, or whatever it is that you are measuring. Pictogram charts also come in handy when you want to clarify confusing statistics. Back in data tip #77, I used the pictogram chart below to compare the attendance of students in classrooms with attendance monitors to the attendance of students in classrooms without monitors, assuming 10 students per class. The chart was designed to clarify this statement: “54% more students with monitors improved attendance than students without monitors.” That sounds like a lot until you look at the chart below. The 54% stat is a “relative difference,” which is calculated as the absolute difference divided by the “standard” which, in this case, is the class without monitors. So 4.0 minus 2.6 divided by 2.6 or .54, which when expressed as a percentage is 54%. But the chart makes it clear that we are talking about 4 students vs. 2.6 students, which sounds much less impressive than 54%.
Warnings
Avoid showing too many icons. They are hard to count. Remember that one icon can represent a larger number. Also, don’t display partial icons. If you need to show a number with a decimal, consider showing the whole icon and coloring in just part of it, as in the example above.
Fun Fact
You can find free icons to use in pictogram charts at The Noun Project or at Flaticon.
To see past data tips, including those about other chart types, click HERE.
Let’s talk about YOUR data!
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