A conservative government would introduce a new league table measure, based on a GCSE points system, to stop schools focusing on borderline CD- grade pupils.
Michael Gove, Shadow Schools Secretary, also told The TES that some coursework would survive, contrary to reports this week.
He is concerned that the current measure - five or more A-C GCSEs, including English and maths - is leading schools to neglect the very brightest and the least able pupils. Instead he proposes a measure, similar to A-level league tables, that would score pupils and their schools according to each GCSE pass gained.
"My view is that a points system would be the one measure that most people would look to," he said.
His proposal came as three pieces of guidance emerged - from the secondary National Strategies programme, the London Challenge and National Challenge school improvement teams - all suggesting that schools focus most of their efforts on CD-grade pupils.
The National Challenge document proposed a "tactical approach for teaching and learning" and "fine-tuning teaching and planning to focus more closely on the exact requirements of grade C", according to a Daily Telegraph report.
Mr Gove also proposed measures to show which schools have the most passes in "all the core academic subjects" - English, maths, the sciences and a language. The aim is to reverse the trend towards "soft" subjects such as media studies.
This would be one of several measures that could be used to compile league tables. "The more information parents have, the better," said Mr Gove. "They should be able to form their own judgments about what's important."
On coursework, Mr Gove said it was important to keep up with the "best- performing" systems such as Singapore and Taiwan, where there is more emphasis on the "rigorous testing of knowledge".
He said the details would be determined by the review into testing and assessment he has commissioned from Sir Richard Sykes, former rector of Imperial College London, due to report later this year.
"One of the briefs for Sykes is to work on the basis that reducing coursework should be an aim," said Mr Gove. "But obviously there will be specific examples where Sir Richard and his team say, `We believe it serves a purpose here'."
Results analysis, pages 22-23.