The easiest subject in which to achieve a C grade at GCSE is drama, academics at Durham university revealed this week.
Physical education, media studies, English and sociology are next easiest, while statistics, chemistry, physics, biology and Spanish are the hardest.
The findings - based on the GCSE performance of an entire year group of 600,000 pupils in 2004 - will be seized upon by teachers, pupils and parents, some of whom will be looking for soft options.
Others, however, will argue that pupils might be getting better results in supposedly "easier" subjects because of better teaching. The research also has no way of factoring in whether students have a particular talent for a subject or interest in it.
The figures will alarm the exam regulator, however. It has argued that all GCSEs are equally difficult to do well in.
The researchers factored general ability levels of pupils into the analysis, though not aptitude in specific subjects. They used a model which compared the result each pupil achieved in each GCSE.
They concluded that, students, whatever their ability, would be more likely to achieve good grades in subjects such as drama and PE, than in science and languages.
Robert Coe, director of secondary projects at Durham university's Curriculum, Evaluation and Management Centre, who led the research, said:
"It's hard to deny that there are differences in the difficulty levels of particular subjects."
It had been put to him, he said, that pupils might be achieving better results in subjects such as physical education and English because the teaching was better. In addition, there was the issue of motivation.
Results could be worse for a subject such as statistics because pupils did not devote as much time to preparing for it.
But Dr Coe said it was unlikely that this explained all of the differences.
The analysis is powerful in that it offers more information than can be gleaned by analysing "raw" results in GCSE subjects each year.
John Dunford, general secretary of the Association of School and College Leaders, said: "We have always known that some GCSEs are harder than others.
"Students at age 14 will take the subjects in which they can do best, and in a sense there's nothing wrong with that." However, he said, it was a problem that subjects such as languages were "harder" than others, confirmed by the Durham analysis, as pupils shunned them.
They would avoid A-levels in languages and physical sciences - yet these were vitally important to Britain's future prosperity, he said. "Every attempt should be made to make papers the same standard," he said.
Dr Coe said he had attempted to consider how "easy" General National Vocational Qualifications were. But his analysis had been confounded by a striking finding: pupils with high grades in GCSE subjects did no better in the most popular GNVQ than those with low grades.
Dr Coe said this suggested that GNVQs were measuring "something different"
from GCSEs so comparison was difficult.
A spokeswoman for the exam regulator, the Qualifications and Curriculum Authority, said: "The QCA works to ensure that GCSE standards are consistent across different subjects."
Major GCSEs ranked by difficulty, with the hardest first:
Chemistry. Physics. Biology, Spanish. German, French. History. Science (double). Geography. ICT. Science (single). Maths. RS. Business studies. English literature. Sociology. English. Media studies. PEsport. Drama. Source: Durham university