[diognesofsinope]

I get why it's used, but I strongly believe people are better off seeing the raw data. Exactly as you said, we can probably infer if there is variation in testing (weekends).

Or at the very least show the 7-period SD so we can see if the confidence intervals overlap.

You can absolutely use averages to hide data points and data quality.

PS: I disagree with your PS -- if we're being wildly theoretical and impractical about this we should just create a second Earth where everyone wears mask and a third Earth where no-one wears masks and compare all the Earths....

And none of what you're saying addresses the core problem I mentioned, which is that the divergence in the series starts before the policy date.