Cheat Sheet: Choosing the right chart for Data Visualization

So, you’ve been working on a data set, be it a relatively short table of experimental results or an almost-impossible to describe excel composed of multiple fields and countless rows. Now, you need to share your findings in a report or presentation. While you could copy the raw data into your output, that would likely be difficult and unpleasant to read and digest. A better way to show off the relationships and insights you discovered is via a chart summarising the data. The old saying is that a picture is worth a thousand words but did you know that 90% of the information processed by the brain is visual? With that in mind, let’s get into the different types of visualisations available and when to use them.

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“Effective data visualization can mean the difference between success and failure when it comes to communicating the findings of your study, raising money for your nonprofit, presenting to your board, or simply getting your point across to your audience.”

Cole Nussbaumer Knaflic In her book Storytelling with Data

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The first question you need to consider is, what is the goal of this chart? What do you aim to achieve or communicate? Keeping that in mind, the charts we are discussing today can be grouped by communication goal. 

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Different Communication Goals

Inform: convey a single important message or data point that doesn’t require much context to understand

Compare: show similarities or differences among values or parts of a whole

Reveal Relationships: show correlations among variables or values

Once you decide on the goal, you can consider your options.

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Inform

How do we highlight the key info

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Single Large Number 

When to use:

• You have one, important, flashy stat to land 

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Donut Chart

When to use:

• simple proportions 

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Pictograph

When to use: 

• Simple proportions 
• When your target audience prefers icons and pictures 
• Show progress of a goal or project
• Highlight ratings 
• Share survey results 
• Share level of proficiency

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Compare

How do we compare categories or show how items are broken down

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Bar Chart

When to use : 

• If you have more than 10 items or categories to compare 
• If your category labels or names are long

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Stacked bar chart

When to use: 

• Similar to bar chart but useful if there is a third qualitative dimension to include 

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Pie Chart 

When to use:

• Illustrate part-to-whole comparisons  — from business graphs to classroom charts
• Identify the smallest and largest items within a data set
• Compare differences between multiple data points

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Reveal Relationships

How has the data varied over time or against another variable

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Line Chart

When to use:

• Compare and present lots of data at once
• Show trends or progress over time
• Highlight deceleration 
• Present forecast data and share uncertainty

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Scatter Plot

When to use:

• Show relationships between two variables
• You have two variables of data that complement each other

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Area Graph 

When to use:

• Display how values or multiple values develop over time
• Highlight the magnitude of a change
• Show large differences between values

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Hopefully, after reading this you have a better understanding of your data visualisation options and when to use them. Keep learning! This is a non-exhaustive list and there are other options available to you. Also, software such as Power BI and Tableau are a great resource to level up your data visualisations and make interactive views. More on those to come x