The second of three studies looking at the quality of designated recommending bodies (which supervise candidates undertaking training in schools) and the GTP courses they run, found that the on-the-job training programme was also filling vacancies in parts of the country where it was difficult to recruit. Four out of five lessons carried out by GTP trainees were deemed to be satisfactory, and more than half were found to challenge pupils.
Under the scheme, trainees are paid pound;14,000 a year. One in six of the 40,000 teachers trained every year comes through the GTP route.
The report, of 47 of the 107 designated recommending bodies, found that most of those inspected had established appropriate management and quality assurance procedures. However, there were concerns that these were not implemented rigorously enough to ensure consistent high-quality training in all partner schools. Improvements also needed to be made to match trainees to good placements and monitoring of whether their individual training needs were being met.
Said Ofsted: "GTP trainees showed strengths in their classroom organisation and were often more confident in managing pupils' behaviour than those trained through postgraduate certificate in education (PGCE) courses.
"The GTP trainees demonstrated a narrower repertoire of teaching methods than PGCE trainees, They also were less secure about how to plan effectively and how to use assessment to support pupils' learning."
It added that there seemed to be a " close relationship between the quality of training provided by the designated recommending bodies and the quality of teaching that the GTP trainees achieved".
About a third of the bodies paid insufficient attention to how secondary trainees should teach their specialist subjects and how pupils learn them.
A similar proportion had weaknesses in their assessment of trainees.
But inspectors were impressed with the quality of primary trainees who, they said, were performing better than their secondary colleagues.
Miriam Rosen, Ofsted's director of education, said: "Management is improving and if DRBs and schools implement and monitor strategies for improving subject-based training we could see some rapid improvements. I am confident that the good examples shown throughout Ofsted's report can be extended across the graduate teaching programme as a whole."
A spokesman for the Department for Education and Skills said the scheme was being rigorously monitored and no under-qualified teacher would get into the classroom, adding that 32 of the 47 designated recommending bodies inspected were meeting the standards.
However, John Howson, The TES recruitment expert, said it was "scandalous"
that some DRBs were still failing to reach acceptable standards of training: "If this scheme is to continue to train around ten per cent of our teachers, then it has to be of the same high quality as every other route into teaching."