To cut or not to cut (the Y
Cutting or not cutting the Y-axis is probably one of the most disputed topics in data visualization, as here,hereand here. Basically, the issue is whether or not the Y-axis should always start at zero. Let’s try to find out why it is a struggle to gain consensus on this topic.
When it is good
“In general, in a time-series, use a baseline that shows the data not the zero point” - Edward Tufte
So how to choose
By its design, a bar graph emphasizes the absolute magnitude of values associated with each category, whereas a line graph emphasizes the change in the dependent variable (usually the y value) as the independent variable (usually the x value) changes.
- Barplot: With this kind of chart there is consensus: your Y-axis should starts at 0
- Line plot: Here however there is no consensus, even if in general you don’t have to start at 0.
Read more:
- Have a look to this #SWD challenge by storytelling with data: you will see that most of the entry ordered their barplot.
- Read more about barplot and lollipop plot
- Have a look to the collection of dataviz pitfalls: