What is the statistically sound way to find out if the the length of projects are decreasing over time ?
The obvious one is to just take an average of all finished projects each month and see a change. But at the start of records it will be unstable and as you get to the present it will become more and more stable and harder to move the average.
I don't think so because the month they finish is not related to how long they take. And for live reporting the data output changes this month if for instance next month a very long project finishes.
What is the statistically sound way to find out if the the length of projects are decreasing over time ?
The obvious one is to just take an average of all finished projects each month and see a change. But at the start of records it will be unstable and as you get to the present it will become more and more stable and harder to move the average.