# Matrix Variance mode

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This mode is only available when a matrix is active; it is not available in Summary view.
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Matrix Variance mode takes an existing matrix and adds additional columns, to show the previous period and variance. It is effectively a combination of Matrix mode and Variance mode. Matrix Variance mode is useful if you want to compare an existing matrix with another period, for example, last year, month or quarter. 

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Matrix Variance and Matrix Share mode
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The following example uses Matrix Variance mode to identify which customers have bought downlights but not transformers, both this year and last year:

1. Start with an existing a matrix (this example continues with the example in the [Compare data with Matrix mode](https://docs.phocassoftware.com/analytics/compare-data-with-matrix-mode) page).
2. Select **Mode** > **Matrix Variance**. The grid updates to display additional columns for the previous period and the variance between the current and previous period.

   <figure><img src="https://content.gitbook.com/content/itAvDF3MljQXV0rjHRP7/blobs/pdBejM2I9t572biJiZQM/2994438470.png" alt=""><figcaption></figcaption></figure>
3. (Optional) Go back to your regular matrix: click **Mode** > **Matrix**.&#x20;