Chart creators often extend the quantitative scale in their charts to include zero when it’s not necessary, or don’t extend it to zero when it is necessary. Making the wrong design choice can make charts hard to read, distort readers’ perception of the data, or hide key insights. Expert opinions differ on when it is and isn’t necessary to extend a chart’s scale to zero, but most of the opinions that I’ve seen are, I think, too simplistic. Determining when zero is or isn’t necessary is surprisingly complex and multi-factorial (hence this 4,600-word article), but it can be captured as a decision tree of rules that chart designers of any experience level can follow to guide them to the right choice in any situation. Feel like coming down the rabbit hole with me to find out what are all of the factors that affect this decision?
Read moreThe biggest misconception in data visualization
When designing a chart, most people try to come up with the ‘best way to visualize the data’. This often results in charts that are unobvious or useless to readers, though. Instead, we should try to design charts that best answer a specific question or that best communicate a specific insight about the data, even though such charts don’t answer all questions that readers might have about the data.
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