How do I make an effective chart for a PowerPoint presentation?

The more numbers that you put on a slide, the less clear your message will be.

No matter how hard you try, sooner or later, you’re going to include some real numbers on a PowerPoint slide. PowerPoint makes it so easy to create charts. Unfortunately, PowerPoint makes it so easy to create bad charts. Here are some ways to make those charts more meaningful.

Keep Your Point Clear

Every slide with data on it should be advancing some argument that you’re making. Sure, reviewing raw data is great and useful research that takes place in places like the National Institute of Health, but most of us don’t sit in those meetings very often. In other words, there needs to be some reason the numbers on the slide are even there. What point are you trying to make? The numbers shouldn’t just be sitting there.

For example, take a look at this example slide from Garr. Garr compares how various countries have access to internet on their cell-phones. He includes data from the UK, France, and South Korea, to name a few. He’s probably trying to point out how South Korea, particularly, has a high degree of internet access. Now, the rest of that data from the other countries is great for showing credibility. However, the additional data does pull attention away from the point he’s trying to make.

See how it might be redone.

Let’s suppose you’re addressing a US audience and you’re trying to pitch your new South Korean Internet venture to a VC. You want to show how Korea is so much bigger than the US in Mobile Internet share. To keep your point clear, keep the US as the reference point, since Americans tend to anchor on their own data. Otherwise, the audience will have to work that much harder to figure out what it all means.

Now, a subtle point: putting the bars sideways was silly. It takes too long for audiences to read the data sideways. Always go up - height has instant meaning.

Also, the closer you get to 100% the harder it becomes. When it comes to networked things like fax machines, for instance, 40% may be ten times more valuable than 20%, not just twice as valuable. So, you had better draw a picture of cell phones. The US phone is a little broken. Korea is nearly done. Notice how the revised slide focuses on South Korea and lets you make the direct comparison with the US.

Don’t Be Stingy with Slides

A presentation is not a printout. A presentation is to create action. There’s a dynamic element where you can sequence things. Why not first show the US-only slide to set the baseline? “Only about a third of US cell phones can reach the internet. And there aren’t many services.”

The audience can quickly grasp and check this “fact.” Since they can verify it easily, they will believe it, and they will own it. That’s way better than lots of unreadable numbers that won’t be understood.

It has a second effect. The fact that the left side of the slide was so empty makes them curious for what comes next. Then, show all three countries and state, “When penetration is nearly total, that changes everything.”

Now, you’ve got them aligned and receptive, and extra slides don’t cost anything. So, don’t be stingy with slides!

Pie Charts

One last tip. You can (nay, you are expected to) group data. Where this typically goes wrong is in pie charts.

Consider the typical pie chart showing where a website’s traffic comes from.

It accurately represents more than six different sources of traffic for a website. But the pie is too hard to grasp. It has no point. Accurate? Yes. Actionable? No.

Regroup the same data into three sources instead. One of them is bigger. There will be one and only one that can be scaled. Your attention will have to focus on growing that slice. That is infinitely clearer and advances your argument better.

All the data is welcome, sure, but stick it in a handout, and hand it out after your talk.