Under-performing pupils were removed from Birmingham's secondary schools months before their GCSEs in their own "best interest" education chiefs claimed.
The move has attracted criticism because the youngsters were not included in the city's overall pass rate last year, boosting the authority's performance in league tables.
Education scrutiny officials claim the move raised "massive questions" about how schools deal with difficult pupils.
They will question the authority today about the practice, which was high-lighted by The Birmingham Post last November.
Nearly 430 Year 11 youngsters were taken off roll at 63 secondaries between September 2004 and January 2005.
Of those, 201 were referred to alternative educational provision, mainly with vocational training providers, colleges and behaviour support units.
Most of these - 57 per cent - failed to gain any qualification at all.
Birmingham City Council maintained a Year 11 pupil was only moved into alternative provision after "full consultation", that included parents.
"This provides an education programme that meets their needs and gives them the best possible opportunity to achieve a positive outcome," said a spokesman.
"At all times the best interest of the pupil is at the heart of any move from being on roll to alternative provision."
Out of the 427 pupils taken off roll, the authority had no idea where a further 111 of the pupils ended up. An additional 81 moved out of the city to other authorities or countries; 17 refused to attend school; six were at independent schools and three had long-term illness and eight were listed as being in custody.
If included, the city's pass rate for five or more A* to Cs would have dropped from 56.7 per cent to 55.2 per cent. The national average pass rate last year was 57.1 per cent.
Coun Jon Hunt (Lib Dem Perry Barr), chairman of Birmingham's education scrutiny committee, said: "We will be trying to make sure that if young people are advised to go to alternative provision like a college, it is suitable for them and is going to take them forward, rather than fobbing them off on someone else."
Coun Hunt added it was also vital the authority was "assertive" in tracking down youngsters who dropped out of education and went missing.
Coun Les Lawrence (Con Northfield), cabinet member for education, claimed the practice of referring pupils was aimed at keeping them motivated in learning.