Correlation Matrix

Correlation Matrices are color-coded tables showing degrees of correlation among a set of variables.

Correlation Matrix


Use When

  • Representing the statistical correlations between pairs of variables in a set.

Don′t Use When

  • Representing the distribution of items across two axis variables, absent of statistical correlation values.
  • Displaying the distribution of a set of items relative to three variables, one of which is expressed through the size of the plotted item.

Visual Language

  • Always use an even number of ranges within the legend scale, equally split between positive and negative correlation.
  • The positive and negative correlation ranges each have a base color, $mds-visualization-color-correlation-positive and $mds-visualization-color-correlation-negative to represent the range including the edge value (1 and −1 respectively). The subsequent ranges in each should utilize tints of the base color. These tints can be adjusted to match the distribution of the number of ranges, i.e., 25% tints could be used with 8 total legend items, while 30% may be more appropriate with 6 total legend items.
  • Never assign new base colors to the Correlation Matrix. The base colors should remain consistent across implementations to help recognizability and understanding.
  • Use mirroring to duplicate the data allowing for either axis as a starting point for comparison.


  • When the data cells become too small to contain the text, the cell displays only a color value.


  • Strive for short, succinct item names that clearly describe the data.

Code Reference

Necessary code documentation can be found in the MBC repository.

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