Thanks for the reply.
Yes, mostly that is what I want to do.
I am comparing for example yesterday which was a Sunday (April 21, 2019) to the "same" Sunday of April of last year (April 22, 2018), and each of the 28 days preceding yesterday to the same period last year.
Right now, my view in the line graph plots each line so that they match the exact days (e.g. 04/21/19 vs 04/21/18). Put differently, this view shows the 111th day of 2019 vs. the 111th day of 2018. Instead I need it to compare the 111th day of 2019 to the 112nd day of 2018.
Changing -366 to -364 as you suggest above doesn't seem to help with this unless I'm doing something wrong? Does what I'm trying to do make sense?
Sorry for late response. We use these metrics everyday at work, we call them "Prior Year Same Day (PYSD)" measures, although these are calculated in database in SQL but the logic is similar in Tableau. Have you also changed the ending date(the range should be between 364 and 392 to account 28 days)?