The Dot Plot is my second favorite chart type to display data—especially if it matches the original design of William Cleveland; First place belongs to the Scatterplot.
Dot plots have many advantages over standard ways of displaying categorical data—such as the bar graph or the pie chart.
First, dot plots use position to encode quantitative data—more accurate in conveying quantitative information to the viewer compared to bar graphs that use length and pie charts that use angle or area as an encoding mechanism.
Second, dot plots use less ink, and hence are less cluttered (plus the added benefit of reducing your printer's cartridge expenditure).
And third, scales don’t have to start at zero—generally, a requirement for bar graphs. This allows for narrowing down the range on the scale and consequently more differences can be noticed in the data.
Naomi Robins wrote a thorough article explaining the benefits of dot plots as an alternative to bar charts.
Let’s say I want to visualize the data shown in the table below to compare traffic fatality rates by state for the year 2017 in the United States.