Dot plots (dot graphs) use dots or points to represent data values along the y axis, in the same way that bar graphs use differently sized bars.

Using dot plots

Dot plots can be used for charting data values across discrete groups or categories along the x axis, or for frequency data across a range of values on a measure along the x axis (i.e. analogous to histograms).

Single dots can be used to represent the total or upper bound of the data value for each group or category. Alternatively, a ‘tower’ or line of dots can be used to represent a count or amount for each group:

Dot plots used to represent data values of the number and age of children enrolled in Healthy Kids program..

Drawbacks of, and alternatives to, dot plots

At first glance, or for people who are unfamiliar with dot plots, these graphs can be mistaken for scatter plots or line graphs, which also use dots to represent data values. This can be confusing for the reader because each of these graph types is traditionally used to show quite different data relationships. For graphs that include a large number of categories, the reader may also find it difficult to align the dots with their categories along the x axis.

Tip. Instead of dot plots, use histograms and bar graphs to display frequency data or compare data values across discrete groups, respectively. Rectangular bars stand out more clearly, and can thus be compared more directly by the reader than floating dots. Bars are also anchored to the category or value on the x axis that they represent, whereas dots can be difficult to align visually with their x-axis label.