Children are feeling stressed, anxious and afraid to fail due to a "targets" culture in schools, a poll has found.
Too much focus on meeting targets is having a "hugely detrimental" impact on pupils' education, according to the Association of Teachers and Lecturers (ATL).
A poll conducted by the union found that pressure to meet particular objectives damages the quality of teaching, with teachers "teaching to the test" and leaving less time for practical or creative work.
In total, more than half (53%) of the school staff questioned by ATL said that targets make their students fear failure and make them stressed.
A further 49% said they increase students' anxiety levels, with 42% saying that they lower pupils' self-esteem.
The survey goes on to indicate that targets make little difference to many students' school work, with 45% of staff saying they have no impact on how hard students work and 44% saying they have little effect on grades.
But it also found that half of teachers think that targets help students to focus on a goal.
More than half of the school and college staff questioned thought that specific objectives have a negative effect on quality of teaching, with 79% saying they make it difficult to teach a broad curriculum.
ATL is due to debate a motion on the issue of target setting in schools at its annual conference in Manchester this week, highlighting the impact that targets have had on the NHS.
The resolution calls on the union to investigate the effect that this issue is having on pupils, staff and learning in general.
The poll reveals that three fifths (60%) of teachers think that a focus on targets means that they "teach to the test", with over a third (36%) making students spend as much time as they can practising for exams and tests.
One secondary school teacher from Peterborough told the union: "Rigid target setting based on random factors and bad evidence does not raise educational standards and never will.
"Targets tend to lead to manipulation of grades and achievement."
Around 58% of staff claimed that targets leave them less time to spend on creativity and communication skills, while 38% say they do less practical work with their classes.
More than a third (37%) said they spend less time teaching topics that their pupils will not be tested on, and over a quarter (27%) said they do not teach non-tested topics at all.
One Milton Keynes secondary school teacher said that teachers and schools were constantly trying to leran new ways of meeting objectives that are "impossible to achieve".
Another, from Buckinghamshire said: "GCSE targets are based on Key Stage 2 results (for children aged 11) and a computer programme that says what a child 'should' get, but make no allowance for the fact that we are working with teenagers, with whom there actually is no straight-line trajectory."
Instead of being goals to aim for, targets have become tools for judging pupils, teachers and schools, ATL argued.
Around 61% of those questioned said they think students' progress can be measured and assessed without setting targets, with just 17% saying they are needed.
ATL general secretary Dr Mary Bousted said: "An over-emphasis on targets is having a hugely detrimental effect on children's education.
"In too many cases meeting the targets seems to be more important than children learning and gaining important knowledge and skills."
A Department for Education spokeswoman said: "We totally agree that education should not be an endless treadmill of revision and testing. That is why we are scrapping modules and January assessments to end constant exams and ensure pupils develop an indepth and lasting understanding of a subject."
She added that the new national curriculum is less prescriptive, allowing teachers to use their creativity.
:: The poll questioned 944 ATL members working in state and independent schools and colleges in England, Wales and Northern Ireland.