How likely is it to be readmitted to a university after turning down first acceptance?

If I were to turn down my admission and a deferral year, is it likely to be readmitted again if I apply? The acceptance rate is roughly 25% and I was nearly below average in every category of the accepted profile.

I would like to wait one more year to begin my PhD program, but I am worried I might not get in the second time around. Do my chances increase or decrease if I wait another year? Does it look bad if I turn down my deferral year?

Please do not ask why I’m turning it down - not what I’m asking.

What do you mean “turn down your deferral year”? Did you ask to defer, but found out that you need more than just one year off? If that is the case, ask about the specific length of time needed. Sometimes (especially for students who must complete two years of national military service) that is not a problem at all.

If you already deferred for one year (aka you were accepted to begin Fall 2017 and deferred to begin Fall 2018), you’d need to have a really good reason to decline your admission. Deferral means that you commit to attending the program, you just need a year to take care of some things. You’re basically backing out of that agreement - and have also now disrupted two application cycles. Yes, it does look bad if you decline admission after you have deferred a year.

There’s really no way to predict how likely you are to get admitted. If you were already a borderline candidate (below average in every category) and you decline after deferring another year, many departments would see that as a ding against you unless you significantly improved your profile in between years. Other departments may treat it differently. It’s really impossible to tell.

I’m not going to ask why you are turning it down, but I will say that your reason for turning it down actually is really important here. If you needed another year because you have a sick relative you’re caring for, lost your home in a tornado or a financial crisis, or are recovering from your own illness - those are understandable reasons. Even good things like receiving a Fulbright or other prestigious grant or some kind of opportunity like that, that can enhance your graduate profile and make it likely you’ll return, could be a good reason. But if your reason is that you’d like to work another year, save up more money, just don’t feel quite ready yet for grad school - those aren’t good reasons to decline after deferring admission, and the department is unlikely to look favorably upon that.