The slump in the economy, coupled with the acrimonious discourse over how much weight test results and seniority should be given in determining a teacher’s worth, have conspired to bring morale among the nation’s teachers to its lowest point in more than 20 years, according to a survey of teachers, parents and students released on Wednesday.

More than half of teachers expressed at least some reservation about their jobs, their highest level of dissatisfaction since 1989, the survey found. Also, roughly one in three said they were likely to leave the profession in the next five years, citing concerns over job security, as well as the effects of increased class size and deep cuts to services and programs. Just three years ago, the rate was one in four.

The results, released in the annual MetLife Survey of the American Teacher, expose some of the insecurities fostered by the high-stakes pressure to evaluate teachers at a time of shrinking resources. About 40 percent of the teachers and parents surveyed said they were pessimistic that levels of student achievement would increase in the coming years, despite the focus on test scores as a primary measure of quality of a teacher’s work.

Sandi Jacobs, vice president of the National Council on Teacher Quality, a nonpartisan advocacy group in Washington, said the push for evaluations, punctuated by a national movement to curb the power of unions, had fostered an unsettling cultural shift.