When we calculate week over week change for a metric like "Monthly active users", we often refer to a calculation of SUM(This week) - SUM(Last week)/SUM(Last week), which means we will run total of this week's number first, and then compare to the total from last week. There is another situation when we can have change any date comparing 7 days ago(week), So each date during a week will have a change value.
Are there any best practice for this "week over week" concept. I've also heard that someone is using "weekly change" referring to the similar thing. Is there any difference? Which calculation I should chose?