umich的conditional

Dear XXX:On behalf of the Dean and Faculty of the School of Information, I am pleased to inform you that you have been conditionally admitted to the Master of Science in Information program at the University of Michigan School of Information for fall 2013! In order to change your status from conditional to 'regular' admission, we must receive a final, official transcript that posts the undergraduate degree you earned. We must receive this transcript by the end of your first term of enrollment. All credit hours earned while you are in conditional status will count toward the graduate credit hours required to complete the program.

为啥是conditional AD？ 跟正式的有啥区别呀，求指教~