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title: "Understanding Variance" slug: "understanding-variance" excerpt: "" hidden: false createdAt: "Fri Aug 09 2024 14:04:12 GMT+0000 (Coordinated Universal Time)" updatedAt: "Fri Aug 09 2024 14:04:40 GMT+0000 (Coordinated Universal Time)"

The Variance Decomposition report

Recast digs into your variance to learn about why there may be a high variance in some of your channel estimates. This is visualized in the variance decomposition report. A high variance may be due to lack of spend, or correlation with another channel, spikes or the intercept.

Technical summary

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Setup: for the selected time-period, we sum the daily impact estimates for each channel for each draw to get a 500 x n_channels matrix of (say) total monthly impact.

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