An annual survey sheds light on challenges facing U.S. teachers and school leaders.

School principals and teachers have high opinions of how effectively each group is working to educate students, but principals say their job is growing increasingly stressful and has changed significantly, according to the latest MetLife Survey of the American Teacher, conducted for MetLife by Harris Interactive in late 2012.

The 2012 survey examines how teachers and principals are approaching leadership challenges and requirements within schools and districts.

“This year’s survey focuses on how teachers and principals view responsibility and challenges of leadership in schools as they begin to implement more ambitious standards to increase achievement in schools and beyond,” said Dennis White, vice president of corporate contributions for MetLife.

Principals say their responsibilities have changed significantly in recent years, and the job is morphing into something “too complex and highly stressful.” In fact, three-quarters of principals say their jobs have become too complex, and almost half say they are under a large amount of stress at least several days a week.

A “key insight” from the survey is that many school leaders feel that the biggest challenges to schools are out of their hands, said Dana Markow, vice president of Harris Interactive and the poll’s project director.

(Next page: More on what the survey data reveal)