live in an age where billions of pieces of content are exchanged on a daily basis
I’ll be discussing guidelines for choosing chart types that match different types of online data/information.
Here’s what Dennis Ghyst, our VP of Content and Marketing, had to say about the advantages of infographics in his two-part Insights series on Infographics.
“We live in an age where billions of pieces of content are exchanged on a daily basis – so it’s no surprise that visual aids, especially infographics, have become indispensable (whether static or interactive) in online digital marketing. … (And) you don’t have to be a graphic designer to create an infographic if you use one of the free online tools to guide you through the process”.
Three of the most commonly used infographics include–
- LINE CHARTS
Line charts are a familiar way of presenting trends over time. Examples include week-to-week revenue report views and trends.
Be cautious, however, when interpreting (or displaying) either axis. If the data are conflated, changes can look dramatic when they’re only minor. Purveyors of disinformation often deliberately create such graphics to mislead viewers, one of the many ways that some ‘experts’ lie with statistics.
Line graphs and bar charts can be combined to good effect. In fact, many types of graphics can be combined to reinforce data findings. For example, you might post a bar chart illustrating yearly product sales combined with a line graph indicating growth in market share.
- BAR CHARTS
Bar charts are a great way to compare discrete data highs and lows that highlight change over time. Appropriate subjects could include interdepartmental spending patterns, sales of different car products or a state-by-state breakdown of website viewers.
Another benefit–By combining different, but related, bar charts on one page, you give the viewer access to information that helps answer multiple questions at once, saving them the time and effort of searching through multiple sources .
One of many excellent options is to integrate bar charts with maps. By clicking on a given country, for example, a bar chart could open to show demographic data.
Finally, viewers expect you to use color in all types of graphics, so don’t disappoint them!
- PIE CHARTS
Pie charts are the best graphic for displaying percentages or proportions. However, their use is limited almost entirely to that purpose, making them the most misused of all chart graphics.
Comparing data is better achieved with the use of bars or stacked data. Things get lost in translation when you compare pie charts next to one another. Instead, use pie charts to illustrate things like survey responses breakdowns, or how a budget is distributed across departments.
Another cautionary note–graphics experts recommend you limit your pie charts to six wedges. Things get confusing for the reader, otherwise. Also, as with bar charts, pies can be used to highlight geographical trends.
Three additional chart/graphic types–
Readers love charts and graphs, as long as they’re easy to interpret. Unfortunately, as I stated in Part I of this article, some graphics give the appearance of transparent, valid data, but are deliberately misleading.
The Gantt chart
Gantt charts are an essential project management tool used to illustrate project timelines that help employees stay focused on key deliverables. They can be used to highlight a wide variety of variables, e.g., machine availability over time for different manufacturing teams, etc.
As with other chart types, Gantt charts can be used in combination with maps to show geocoded information, for things like the prevalence of HIV rates by metropolitan area or ranges of income by state. As with other graphics, use contrasting colors within the Gantt chart for easier interpretation.
The histogram (Bar chart)
Histograms are ideal for showing data distributed across groups of data. For example to display the relative heights of 200 professional basketball players, a histogram will display height from low to high along the horizontal axis and frequency along the vertical axis. You could do the same for numbers of students at different colleges/universities or frequency of recall rates for different vehicles.
In addition, you can superimpose a line of best fit (along the top of the bars) to give curvilinear dimension to your histogram.
The bubble chart
Bubbles aren’t so much a chart type as a tool to accentuate data on a background graph or map. People respond well to graphics with bubbles because they so elegantly display different magnitudes of a variable.
Using bubbles as an overlay on a map makes geographically related data easy to grasp.
In Part III of this series, I’ll provide background information on bullet charts, highlight tables, and treemaps.
Use the most vivid color to highlight your trending variable.
I hope you’ve enjoyed my brief introduction to different charts and graphs. As their applications and popularity grow, it’s important you understand which kind of chart to use to make your data clear and accessible. With information increasing exponentially, we all need to better discern the accuracy and appropriateness of graphics used online and in print.
Bullet charts are ideal for tracking progress towards a goal. A variation of the bar chart, it is an effective, elegant replacement for dashboard gauges and thermometers. A bullet graph gives you immediate visibility for the degree to which a primary goal (e.g., a yearly sales quota) has been achieved by individual sales personnel–or, another example–how actual profit vs. projected profit is tracking for a given period, etc.
Contrasting color is requisite to bullet charts. Use the most vivid color to highlight your trending variable. You can also add a dashboard to provide summary insights.
Heat maps are my favorite tool for using color to compare geographically distributed data to focus on high-to-low or strong-to-weak associations. We see how effective heat maps are every day on weather forecasts. They can also be used to great effect to show regional variations in the sales of products and demographic variables like relative income, the prevalence of crime and disease, etc.
You can integrate highlight tables with heat maps to add numbers for greater detail. Demarcated number ranges can also be inserted directly into larger heat maps.
Treemaps use rectangles nestled within other rectangles to illustrate hierarchical proportions of data. Each rectangle is a ‘branch’ with subdivisions that reveal patterns across data, giving you access to an entire data set at one glance.
Treemaps may be used to show computer storage allocations or side-by-side yearly budget allocations. They can be combined with bar charts to provide a quick, effective comparison for the distribution of a specific variable.
Box-and-whisker plot box
Box-and-whisker charts include a box with a distribution of median data (e.g., displayed by quintiles) contrasted with ‘whiskers’ to illustrate truncated data ranges–or maximum and minimum points for the data.
This chart is especially helpful in revealing how data can be skewed in one direction or another, identifying outliers that may be insignificant or indicative of otherwise hidden, but important information.
Using side-by-side boxplots make it easy to compare distributions between sets of data.