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Grouped Scatterplot Chart

A grouped scatterplot extends the standard scatterplot by adding a third dimension: a categorical variable that assigns each point a distinct color. This lets you see the relationship between two numeric variables while simultaneously comparing how that relationship differs across groups.

Grouped scatterplots excel at identifying correlations between two numeric variables while highlighting category differences.

An example of an embedded grouped scatterplot chart

Creating an Effective Grouped Scatterplot Chart

Recommended data types for each axis:

  • X-Axis Numerical values (independent variable)
  • Y-Axis Numerical values (dependent variable)
  • Breakdown Axis Categorical data (each unique value becomes a distinct color)

Description

  • Points - each dot represents one row of data; position is set by X and Y values
  • Colors - each category in the breakdown dimension is drawn in a unique color
  • X-Axis - the independent or explanatory numeric variable
  • Y-Axis - the dependent or outcome numeric variable
  • Legend - maps each color to its corresponding category

When to Use a Grouped Scatterplot

  • Compare correlations across groups - see whether the X-Y relationship is stronger or weaker in one category versus another
  • Identify group-specific clusters - colored points make it easy to see whether groups occupy distinct regions of the chart
  • Detect category-level outliers - a point that sits far from its color cluster stands out even within a busy chart
  • Enrich a two-variable analysis - when you suspect a third variable (like region, product type, or demographic) influences the relationship

When to Avoid a Grouped Scatterplot

  • Too many categories - more than 5–6 colors becomes difficult to distinguish; consider filtering or grouping smaller categories
  • No meaningful grouping variable - if all points belong to one category, use a standard scatterplot
  • Categorical X or Y axis - both axes must be numeric; use a grouped bar chart for categorical comparisons

Further Reading

When to Use a Scatterplot Chart - a deeper look at scatterplot use cases, common mistakes, and alternatives.