Many newly-qualified American teachers are left to sink or swim in their first year in school, a Harvard study has revealed.

In California, Florida, Massachusetts and Michigan, three in four new teachers are expected to shoulder the same teaching and administrative responsibilities as their most experienced colleagues.

More than half of the 486 first and second-year teachers surveyed said they received no help during their first year. Two-fifths of them were not observed by a mentor or more experienced teacher.

“Very few schools acknowledge that learning the art and craft of teaching happens over time,” said Susan Kardos, a researcher at Harvard Graduate School of Education. “Teaching is incredibly complex work and to expect a new teacher to be as effective as a veteran on day one, without additional support, is unrealistic.”

Kardos and her colleagues, Susan Moore Johnson and Edward Liu, also discovered that almost half the new teachers had tried other jobs before entering the classroom. The average age of these mid-career entrants was 38.

“Schools need to think carefully about how to hire and support this diverse group of new teachers, so that they can teach effectively and find success in their work,” Professor Johnson told the American Educational Research Association conference in Chicago.

“Otherwise, schools will be forever searching for new recruits.”