TJL and Towerguy, are you guys referring to the assessment centre, or the 6 month training course itself?
From your comments it sounds like you are talking about the actual training course?
I've been speaking to a few controllers over the past 2 weeks, one is in OJT at the moment and another is recently out of OJT. Both indicated that around 30% of those who went to the assessment centre (final stage of selection process) made it into the ATC program. From there about 50-70% of those who enter the ATC course made it out the other end, they said something very similar to towerguy, that its very high pressure and they are looking to take those that can handle it while "weeding out" those who can't.
From what they tell me the assessment centre is really looking for leadership ability and the ability to work in a team effectively (communicate, co-operate, co-ordinate) and confidently. A bit of sim testing, and a high stress interview.
I'll report back how I found it in a few days!

