Hard questions for hard target 3

Can someone with a better statistical brain than mine explain the government's target for higher education participation? Margaret Hodge has said that "at present more than 43 per cent of young people are entering higher education for the first time by the time they are 30". I can see how you can measure how many of today's school-leavers are entering and how a survey of today's 30-year-olds will give a percentage of who has experienced higher education. What I cannot see is how you can tell how many of today's 18-year-olds will have experienced it by 30 - well, not for about 12 years anyway.

Alan Woodley
Institute of Educational Technology
Open University