Choose the Best Chart to Convey Your Message
You’ve got your data, you’ve made some sense of it, and now it is time to communicate your results. Great! This article will provide examples of many types of charts and graphs and explain how to pick the best one for your data depending on the message you want to convey.
Choosing a type of chart depends first and foremost on what kind of data you have and what you want to express. I find that charts and graphs are typically used to convey one of the following: comparisons/relationships, distribution, trends, composition, flow/process, or location.
1. Comparison/Relationship Charts – Pretty self explanatory, right? You have data on two or more variables and you want to show them together, probably to show a correlation or pattern of some type. Examples might include MPG of three different cars, average heights according to race, etc. Bar charts and line charts, or combinations of the two, are very commonly used for the purpose of comparison.
Venn diagrams are especially useful to show relationships. These are typically qualitative in nature.
2. Distribution Charts – These types of charts aim to convey “what is the distribution?” of my data. For example, let’s say you did a survey and you asked everyone their age. A distribution chart would be usefeul to visualize the distribution of ages among respondents. Column and Line Histogram charts are probably the most common forms of distribution charts. Scatter plot charts are also great for this purpose.
Word clouds are an interesting way to visualize the frequency distribution of words with textual data. Here’s an example of a word cloud from the 2011 Academy Award acceptance speeches. While these aren’t the solution to the world’s problems, they can be useful from time to time in quickly analyzing open-ended comments from surveys.
3. Charts that show Trends – While the chart categories mentioned above can certainly show trends, I think it is deserving to identify this as a category of its own. The most common way to show trends over time is with a line chart. Nowhere is this more common than in showing stock price trends over time. The chart below is a “candlestick” chart.
Here is a good article if you want to learn more about stock market charts.
If you have a few extra minutes, here’s an incredible video of Hans Rosling showing charts in motion, demonstrating both relationships and trends all at once.
4. Composition Charts – The next category of chart types is “composition” charts, which attempt to show viewers “this is how my data is composed.” By far, the most common “composition” chart is a pie chart. A pie chart might show that 60% of my survey respondents were composed of women and 40% were men.
I like using doughnut charts as a variation on the all-too-common pie chart.
5. Flow/Process Charts – Flow charts are used to show–you guessed it–the flow of a process. These are often used to guide a decision. In fact, they are often called “decision trees.” Here’s a couple of examples:
6. Location Charts (Maps) – Geographical maps and data overlays on maps cannot be left off this list. Of course, everyone knows about basic maps, but take a look at some of these map-inspired charts and graphs:
Advanced Charts and Data Visualizations
Most of the charts and graphs shown above are pretty traditional. Data visualization is a hot field and there are many new cool forms of “charts” emerging. Calling them “charts” doesn’t do them justice. I’ll dedicate more time to this in another article, but here’s a sample of what I’m talking about.
That’s about it. I’ve leave you with some links to additional information.
Additional Links and Information
The best guide for choosing a chart that I’ve found to date is this one. They’ve narrowed down the categories of charts down to four.
“Juice Labs” has a nice tool they call the “chart chooser.” It allows you to filter based on your needs.
Finally, here is a nice infographic from online-behavior.com (snipit below) explaining a wide variety of chart types.
I hope this article was informative and that you have a better understanding of the types of charts and graphs out there in the world. If you have any additions or comments, please chime in below.