Adjusting default 'Week' time dimension in time series properties
I've looked at couple threads about issues related to my question, but still can't figure this out.
In a time series chart, I'm attempting to show a rolling, trailing 13 week comparison for given metrics. For example: if comparing last week's ( Sun 3/5 - Sat 3/11) impression count to the trailing 13 weeks (Sun 12/4/16 - Sat 3/4/17), the default 'Week' dimension is set to count a week from Monday - Sunday. Our business looks at weeks Sunday - Saturday, so the data in the time series chart is off & incomplete.
Can I change the way a 'week' is counted by in the time series dimension; and if not, can I create my own unique week dimension? How?