Well, first off, nothing is guaranteed in college admissions. I only applied RD to all of the schools I applied to. And I was shocked to find out that I didn’t get into Northeastern, but I had gotten into Dartmouth. So if you’re positive that Dartmouth is the place for you, apply ED there. If not, then do RD. If you aren’t sure which school is the one for you, then don’t do ED. You shouldn’t do ED only because you’ll have better odds of getting, because that’s not true. And most people get deferred anyways