Reading a Polygon Chart Step by Step

Polygon charts contain more information than they might initially appear to. Once you understand the basic structure, reading a polygon chart becomes intuitive. This guide walks you through every element of a polygon chart and explains how to extract meaningful insights from it.

Understanding the Axes

Each spoke radiating from the center of a polygon chart represents one variable or category. The label at the outer end of each spoke identifies what that axis measures. Values increase as you move outward from the center: the center represents the lowest or zero value, and the outermost ring represents the maximum value on the scale. All axes use the same scale, making it possible to compare values across different categories directly.

Reading Individual Data Points

A data point on any axis is plotted at a distance from the center proportional to its value. If an axis runs from 0 to 100 and a value is 75, the data point appears 75% of the way out along that axis. Once all data points for a given subject are plotted, they are connected by straight lines to form the polygon shape.

Interpreting the Polygon Shape

The overall shape and size of the polygon communicates important information. A large polygon indicates high values across most or all dimensions. A small polygon indicates generally low values. An irregular, asymmetric polygon reveals significant variation — certain axes score much higher or lower than others, indicating strengths and weaknesses.

Comparing Multiple Polygons

When two or more data series are overlaid on the same polygon chart, each appears as a separate polygon with a different color. Areas where one polygon extends beyond another indicate that subject performing better on those specific dimensions. The degree of overlap shows overall similarity between subjects.