Stem & Leaf Plots are a way of organising data via their place value to show the distribution of data.
Place values are shown ascending downwards on a “stem” column, typically but not always in tens. Data that is within each place value is listed and extends sideways from it as a “leaf”.
So in a dataset of (4,11,2,20,17,23) the data would be arranged based on their 10’s digit but have only their 1’s digit displayed:
0 – 2, 4
10 – 1, 7
20 – 0, 3
As well as giving readers a quick overview of the data distribution, Stem & Leaf Plots are useful for highlighting outliers and finding the mode. Displaying the data (mostly) raw makes Stem & Leaf Plots useful as a reference tool, such as a public transport schedule. If you have two datasets, then a back-to-back or double Stem & Leaf Plot can be used to compare the two datasets together.
In terms of weaknesses, Stem & Leaf Plots are limited in the size of dataset they can handle. Too little and they become pointless, too much and the chart becomes over-cluttered.