“Let the data speak.” It’s a common saying for chart design. The premise — strip out the bits that don’t help patterns in your data emerge — is fine, but people often misinterpret the mantra to mean that they should make a stripped down chart and let the data take it from there.
You have to guide the conversation though. You must help the data focus and get to the point. Otherwise, it just ends up rambling about what it had for breakfast this morning and how the coffee wasn’t hot enough.
To show you what I mean, I present you with twenty-five charts below, all based on the same dataset. It’s life expectancy data by country, it’s from the the World Health Organization and it spans 2000 to 2015. Each chart provides a different focus and interpretation.