All children born in Manitoba in 1984 were tracked for 18 years to assess their grade-12 performance on a provincial examination according to a student's socio-economic status. The proportion of youths in families receiving social assistance judged to have passed their language arts exam dropped from 80 per cent to 12 per cent, depending on whether one counts only those in the cohort who took the test on time in 2002 or all youths born in 1984 who should have taken the test in 2002. Getting better data on performance and doing something about the discrepancies should become a Canadian priority. (Contains 5 tables and 3 notes.)