When creating a test event, the norms are determined by the Test Event Date selected upon creation. The Event will maintain this norm even if testing extends beyond the norming date. 

For example, an Event created on November 30th will stay open for the next 30 days, the event will be scored against Fall Norms even if testing is done during December. The same is true for post-dated events, it will be scored against the norming period it was set to with the date, regardless of when testing began or ended.