How to interpret Prophet vars weekday and season

[CarlosalbCb]

Hello, I'm getting negative response in the waterfall chart for the prophet vars weekday and season.
How can I interpret these values for a retail store?

[gedkitchener-CT]

@CarlosalbCb

I would assume that spread over a year, the aggregated (summed) effect of season is zero (by design), and spread over a week, the aggregated (summed) effect of weekday is zero (by design).

So if your total time range isn't an integer number of years then the sum of day-by-day values in season are probably not going to sum to zero, and likewise if the total time range isn't an integer number of weeks, then the sum of day-by-day values in weekday is probably not going to sum to zero.

For example, if weekday (Monday to Sunday) attribution is [-10, -10, -10, -10, -10, +30, +20], then while an integer number of weeks will always sum to zero, I hope you can see that partial weeks will not in this contrived example.

That's my theory - but the authors may correct me.