SOUTH Australia's new high school certificate is leaving boys behind and needs to allow all students the option of studying five subjects in Year 12, a high-level report has found.

The Advertiser can reveal an independent panel found the centrepiece of the new SACE the Research Project provides an "inherent advantage" for female students, most of whom achieved As and Bs.

However, almost half the male students received Cs. It highlighted differences in maturity levels, presentation and personal organisational skills as reasons for the achievement gender gap, which is much greater than in other subjects.

The panel recommends the Research Project remain compulsory but that students have the option to take it as either a Year 11 or Year 12 subject to allow those who take it in Year 11 to study five full Year 12 subjects.

Other findings include:

STUDENTS were studying fewer subjects than their interstate counterparts.

MANY schools and teachers found difficulties with the style of marking and assessment, which created increased stress and workloads.

ENGLISH was compulsory in many other states but in SA, under the new SACE, 66 per cent studied English, down 8 per cent from 2010.

Former senior public servant Bill Cossey led the independent evaluation of the new SACE following criticism that the certificate had been "dumbed down" and lost its "academic rigour".

"The SACE is both nationally and internationally recognised in its current form and there is absolutely no question of the validity of the SACE," Mr Cossey said.

"At this early stage there is no clear evidence that students ... have been disadvantaged in terms of post-secondary school options."

Education Minister Grace Portolesi said the evaluation identified that overall the new SACE was working as it was intended.

"However, it does identify some issues and made some recommendations that now will be considered by the SACE Board and the Government," Ms Portolesi said.

"The specific recommendations and the impact any changes will have on our students need to be properly considered."