Traditional subjects such as history, geography and English top a new league table of A-level courses with the lowest drop-out rates.
Students are more likely to persevere with these courses after the first A-level year than carry on with more fashionable, newer subjects such as psychology and business studies, a TES analysis reveals.
The figures, based on entries to 32 subjects, also provide new evidence that students are dropping courses with high failure rates at AS. This could be helping to increase the pass rate for full A-levels as students ditch the subjects where they got low marks.
Curriculum 2000, which introduced the current modular A-levels effectively gives students a half-way score in each A-level after a year, and the freedom to drop their weakest subjects.
The TES analysis produces a league table of subjects with the highest "staying-on" rates after AS-level, comparing the number of entries at A2 for 2004 with those for AS the previous year.
Top of the table are three "minority" subjects: other modern languages (such as Russian, Punjabi and Polish), classics and Welsh. These are followed by history, geography and English. Bottom are law, general studies and computing.
Newer disciplines, such as psychology and business studies, branded by some critics as "easier", have relatively high failure rates. Some commentators suggest that the high position of traditional subjects in The TES table owes much to them having more academic students than other courses.
The table also reveals a link between subjects with high pass rates, and "staying-on rates".
Of the top 10 courses for staying-on, six also feature in the top 10 highest AS pass rates. Four of the courses where students are most likely to drop out are in the bottom five for AS pass rates.
The correlation is not perfect, however. Maths, for example, is ranked 30th out of 32 on pass rates at AS, but 13th for the proportion who stay with the subject into the upper sixth.
Last week, Ellie Johnson Searle, of the Joint Council for Qualifications, said: "Most students are making very informed choices (at the end of the first year) about moving forward with the three subjects they are best at.
"It is one of the big advantages of having that AS benchmark at the end of the first year."
John Dunford, general secretary of the Secondary Heads Association, said the results showed that the AS results were helping students to decide which subjects to continue with, rather than wasting two years on a course to which they were not suited.
He said: "AS is the filter which leads to a much higher level of success at A-level, which is a very good feature of the system now."