Many of the government's academies are revamping the curriculum, but fewer are changing term times or the length of the school day - contrary to popular belief.
The main reasons for choosing to take academy status are freedom from local councils and the financial benefits, a study has found.
Around one in four (23%) think it will mean better outcomes for pupils.
Just 5% say their main reason for switching was to reshape the curriculum, with the same percentage saying they feared being left behind.
Even fewer said they had become an academy to change term dates and school hours or to set different pay and conditions for staff, contrary to reports in June of some schools opening six days a week, 51 weeks a year.
The study, commissioned by education law firm Browne Jacobson with the Independent Academies Association, is based on a survey of 151 headteachers in primary and secondary schools which have become academies since August 2010.
The findings show that while many new academies did not convert to change the curriculum, half of those questioned have done so.
Just 9% have made changes to lengths of terms or school days while 8% have set their own staff pay and conditions.
The survey also found that not all schools have found the conversion process straightforward.
Eight out of 10 said lack of clarity over funding was an obstacle either during or just after they converted.
Nick Mackenzie, education partner at Browne Jacobson, said: "The ultimate goal of the academies programme is clearly to drive up standards. Whilst it may be too early to assess its impact on achievement levels, ministers will be buoyed by the news that the vast majority of head teachers envisage academy status as impacting 'significantly' on pupil outcomes.
"Whilst the government has taken steps to simplify the conversion process, many clearly still face a myriad of challenges and obstacles that need to be addressed."
Academies are semi-independent state schools which receive their funding directly and have more control over areas including the curriculum and staff pay and conditions.
The schools were originally set up under Tony Blair's Labour government and were aimed at boosting standards in the poorest areas.
Education Secretary Michael Gove has opened up the scheme to all state schools, with more than 1,800 converting so far.