I had an interview last week and was told on the day that I was a strong candidate and that they would be in touch... before bothering to let me know they weren't going to offer me the job, they readvertised it. So that was a nice way to find out. I assume they do it because they're hoping to attract different candidates, one of whom might be a better fit for the school than the ones who applied first time round. I personally wouldn't reapply on principle, as I wouldn't want to be employed as second best (if they actually wanted you they'd have employed you first time round). But then again I do get on my high horse about things like this! If you are still interested in working there it's probably worth a phone call to ask if previous candidates should reapply - apparently sometimes they put "Previous candidates need not reapply" or something if they're not interested, so if the ad doesn't say that it might be worth letting them know you're still available.