Causality and Correlation

Eating kale increases calf muscles by 300%!

Babies born on the 10th of the month solve puzzles 50% faster than those born on the 11th!

Sandal-wearers make 20% more income than those who wear closed-toe shoes!

You’ve heard all the claims and know the stories. Ah, but there’s a sucker born every minute, as P.T. Barnum (maybe) said. If you’ve ever been to the grocery store checkout aisle or watched the news on T.V., you have probably heard extreme claims like the ones listed above. Each of these is an example of correlation—where someone claims one thing causes another thing, but they are unrelated. It’s a case of this ≠ that.

So, be careful what you believe. Be a skeptic. Ask for proof.

Causality in Design

Designers create products, services, and systems intended to cause change. We make a poster to inform people about a concert so they will want to attend. We make an insulated coffee mug so people can drink coffee and not scold their hands. We make a check-in process so people can get their kids into daycare safely and quickly. When designing, think carefully about causes.

• What do you want your design to cause?
• If your design is successful, what will that look like? What will happen?
• Is your product, service, or system designed in such a way that it will be successful at causing the outcome you desire?

When you design, think about your outcome as an intervention. You are making something that will intervene in someone’s day. It will stop them and will redirect them in a new direction. This simple reframing can help guide design decisions like what typeface to use, if an app is appropriate, or if steel or wood is a better material for the job.

Whatever you make will cause something to happen. Plan your causes carefully!