This article describes how to create a correlation matrix that visualizes the correlations between variables as a heat map.
Requirements
- A data set containing two or more variables which have a Structure of Numeric or Numeric- Multi. Note that binary categorical variables can also be used as inputs but will be converted to numeric when calculating the correlation coefficients. See Variable Sets for more info on how to set the measurement scale and values for analysis.
Please note this requires the Data Stories module or a Displayr license.
Method
- From the toolbar, select Table > Specialty > Correlation Matrix.
- Select your inputs from the object inspector using one of the following methods:
- With Data > Data source set to Variables (this is the default setting) or Variable sets, select two or more Numeric or Numeric-Multi variables from the Variables dropdown box. This will run the correlation on the respondent-level values - for example the raw data for brand attitude across different brands:
- Change Data > Data source to Table and then select your table from the Table dropdown box. Rows and columns that you don't want to include in the analysis can be specified by entering them in the Ignore field. Using a table as the data source runs the correlations on the values shown in the table comparing the columns shown. You may want to do something like this if you want to see a metric over time -- for example brand attitude over time:
- With Data > Data source set to Variables (this is the default setting) or Variable sets, select two or more Numeric or Numeric-Multi variables from the Variables dropdown box. This will run the correlation on the respondent-level values - for example the raw data for brand attitude across different brands:
- Choose the Correlation Type:
- Pearson (default) - based on the actual data.
- Spearman - based on the ranks of the data (this is less susceptible to outliers and thus less likely to represent the true nature of the correlation).
- Click the Calculate button (or tick the Calculate Automatically checkbox at the top of the object inspector) to generate the correlation matrix.
Next
How to Conduct a Test of Correlation Between Two Variables
How to Create a Scatterplot Matrix
How to Create a Table of Coefficients from a Correlation Matrix