Hello @gfi1ippou ,

Thank you for contacting us!

In your modeling, you can use discount coupons or product discounts as non-media treatments as they are not directly related to media and have no direct marketing cost associated with them. For additional details, you may refer to our documentation on non-media treatments.

Please ensure that the time granularity of the discounts data matches the time granularity of rest of the data, i.e., if you are running a weekly model, then you may need to aggregate the daily product discounts data to match their time dimensions. For optimal model performance, we recommend using data at the weekly level as weekly data strikes a beneficial balance between variability and noise, outperforming both daily and monthly data.

Thank you

Google Meridian Support Team