It came with a letter and a corresponding answer key, requiring the recipient to fill it out like a formal exam to test their own level. If their score was good enough, they could then come and register in person for the actual test.
The exam was divided into a written test and an interview, and candidates would be accepted in descending order of their scores.
For the sent-down youths who weren't accepted, if their final score was close to their self-assessment score, the general hospital would reimburse their round-trip travel expenses. However, if there was any suspicion of cheating, they would have to bear the loss themselves.
The round-trip fare wasn't cheap. As soon as everyone saw this rule, they suppressed any clever little schemes they might have been hatching.
