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facebookincubator / GeoLift

GeoLift is an end-to-end geo-experimental methodology based on Synthetic Control Methods used to measure the true incremental effect (Lift) of ad campaign.
https://facebookincubator.github.io/GeoLift/
MIT License
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Use weights to manually recreate synthetic control #81

Closed max-kozlowski closed 2 years ago

max-kozlowski commented 2 years ago

How do I manually recreate synthetic control given the model weighs? Is that simply a weighted sum across the control geos? I tried doing this a while ago and I couldn't get to the same numbers.

ArturoEsquerra commented 2 years ago

Hi @max-kozlowski! As you mentioned, the synthetic control can be calculated as the weighted sum of the units in the pool of controls using the SCM weights. It is important to mention that this calculation will yield the average synthetic control unit. If you want to obtain the sum of the synthetic controls (which is what we plot and output in the code), you simply need to multiply that average synthetic unit by the number of test units.