[solidasparagus]

I see where you're coming from and I agree with you overall, in particular how this is a first cut approximation.

But I still want to nitpick the details a bit. If you want to determine whether there was a change in the failure rate, you need to use rate statistics - failures per service-hour. Your analysis is only using the numerator while we know the denominator (the number of services in GitHub that can go out) has increased over time - GitHub Actions and Packages are relatively new.

[srean]

Totally agree with your second paragraph. As I said it was more of a text bookish exercise. If the volume of traffic in the two periods were available, it would have been possible to do the kind of analysis you indicate.