Hari Patience-Davies shares her rules for building charts in PowerPoint and others.
Charts are incredibly useful things – and anytime you’re presenting data, being able to put that data into a nice neat chart is a presentation win. PowerPoint, Excel and many other pieces of software make building charts so easy that it can be tempting to just dump your data in and let the computer do the hard work for you.
But while that may be quicker it often means the charts produced aren’t as good as they could be.
So here are my rules for creating charts, be it in PowerPoint, Keynote, Excel, or Sheets.
Keep things simple
While it may be tempting to cram as many charts as you can onto a single PowerPoint slide, the best data presentations stick to one chart per slide. The only time you should ever have two or more charts on a slide is when you want to see them side by side for comparison purposes – if the data isn’t being directly compared the charts can be separated out – and that’s okay, because remember, PowerPoint slides are free.
We also want to keep things simple in the chart itself – does it need a key or is that taking up valuable space or coming up as too small to read?
In this chart I have chosen to use one colour to show 2020 data and one to show 2019 data, but I haven’t differentiated between which line is page views and which is unique users – and in fact in order to make the key readable I’ve had to abbreviate the descriptions to PV and UV, which doesn’t help anyone who’s reading this cold.
The key isn’t helping me – so I’m going to get rid of it and replace it with text boxes in overlay to provide clearer information.
I’ve now added three text boxes, one shows the colour difference between 2020 and 2019 data and the other two act as titles for the data itself. I’ve also removed the horizontal cross lines to make the chart clearer and easier to read.
This chart isn’t perfect – but it’s now a lot less confusing.
When I first dumped the data for the chart above into PowerPoint, it took the custom colours set up in my deck and gave me this:
I only have a few custom colours set in the deck, and so have ended up with the exact same colour being used for 2019 page views and 2020 unique users – confusing to say the least!
Don’t feel that just because Powerpoint has assigned a colour scheme to your chart it’s one you have to live with.
Remember that 1 in 20 men and around 1 in 200 women are colour blind – and try and design charts which make it easy to see what the different lines are even if someone is unable to differentiate colours at all.
I like how The Guardian’s data storytelling team use grey for background data and red for the data they want you to take notice of – it’s neat, clean and should be easy to understand for the majority of readers. Here’s a good example:
Sometimes changing the colour of just one data point in PowerPoint can be very tricky – so don’t be afraid to hack it by using the shape tool to add a colour box over the bar chart and make the data point you want the audience to pay attention to a different colour. Just be sure to keep the size and shape the same so you’re not accidentally mis-representing the data!
Don’t be afraid of rebuilding
Charts can be intimidating – it’s so much easier to just screendump something out of an analytics software or take charts already built in someone else’s deck and re-use them. But other people’s charts rarely show the same message that you’re trying to convey.
As we’ve established it really doesn’t take long to rebuild a chart in Excel or PowerPoint if you have the original data – and if you don’t you can always fake rebuild it using the shapes and line tools in PowerPoint (if it’s a bar chart, pie charts are harder). Rebuilding a bar chart gives you complete control over the colours of the data points as well, so plan an extra ten minutes into your prep time and make sure the charts you’re sharing are as good as they can be.
Your audience will thank you for it.
Main image by Black ice from Pexels