Exam board researchers have said fraudulent claims of illness from pupils seeking extra marks could be worth tolerating because the system "rescues" candidates with genuine problems.
Extra marks, worth up to 5 per cent of a paper, are available under the "special consideration" scheme which compensates pupils sitting exams for everything from headaches to terminal illness.
But research published today notes that "schools are increasingly wise to the rules" and "it could be argued that people are manipulating the system".
Heads' unions deny the system is abused, despite admitting that schools sometimes have to take parents' word on a pupil's illness.
But the report from Cambridge Assessment, parent company of the OCR board, notes "lots of criticism about how pupils and teachers might be abusing the system to boost results, helping schools climb in national leagues".
The study stresses that less than 1 per cent of GCSE or A-level candidates in any given subject actually have their grade improved by special consideration marks. And it warns there is also a risk of "deserving pupils" being denied extra marks.
"There might be a level of abuse which might be justifiable in order to `rescue' the careers of those worthy candidates," the report says.
Applications for special consideration received by OCR rose from around 30,000 in 2000 to around 80,000 in 2009, the paper reveals.
Figures released last week by exams watchdog Ofqual showed there were 329,000 GCSE and A-level special consideration requests to all exam boards in 2010, representing 2 per cent of the scripts marked, although this represented an 11 per cent drop from 2009. There was also a drop in the proportion of requests approved, from 97 to 95 per cent.
Brian Lightman, Association of School and College Leaders general secretary, said: "Schools obviously want pupils to have the best opportunity to do themselves justice in exams. But the rules are very clear and it is very difficult to see how schools might abuse them, frankly.
"Normally they (pupils) have to have a medical certificate to back it up. Sometimes doctors are not prepared to issue them and it is based on the word of the pupil's parents. It is difficult to know what else a school can do."
Cambridge Assessment's research suggests that the increased modularisation of exams could partly explain the rise in requests. Applications in modular exams are counted as a separate request for every unit applied to. They are also spread out over a longer period of time than linear qualifications, increasing chances of temporary illness or other problems.
The report found that independent schools were more likely to submit special consideration requests than state schools and that high-attaining pupils were more often the subject of requests. Grades were more likely to be improved from C to B or B to A than the crucial D to C threshold.
Carmen Vidal Rodeiro, the report's author, said: "Our research has confirmed that the enhancements were minor adjustments to the marks, with the most popular tariff applied being 2 per cent of the unitcomponent mark."
Special consideration: Dying, bereaved or. headachy
Under the special consideration rules, extra marks worth up to 5 per cent of a paper are available in "exceptional cases" such as pupils with a terminal illness or those who have had a "very recent" death of an immediate family member.
More "minor" problems such as "noise during examination which is more than momentary", a headache, or the illness of another candidate in the exam room, might receive an extra 1 per cent of a paper.
- Original headline: `Sick' exam fakers could be worth tolerating to `rescue' genuine cases