Tests for primary school pupils and 14-year-olds in England should be replaced with teacher assessments, a think tank says.
England retains primary school testing which Wales has scrapped
The Institute for Public Policy Research (IPPR) said "too many" pupils left primary school unable to read and write and do mathematics well.
It said regular teacher assessments of pupils' work should replace the testing of pupils aged 11 and 14.
The report was endorsed by the General Teaching Council for England (GTC).
The IPPR report criticised what it called the negative effects of the current testing regime, which included narrow learning, shallow learning, question spotting and risk-averse teaching.
It said the testing system encouraged "teaching to the test" rather than providing skills for secondary school.
The IPPR suggested pupils should be assessed throughout each key stage by teachers - as they are at age seven in England and in primary schools in Wales.
It said a progress-related target would mean that secondary schools would have to focus on the needs of each pupil, even where average attainment in the school was good.
It proposed that all pupils should be expected to make at least one level of progress between the end of Key Stages 2 and 3 - roughly ages 11 and 14.
IPPR associate director Richard Brooks said parents should get information about how their child is doing from teacher assessment, while sample tests scores of schools would give parents and the authorities an idea of how schools were performing.
"We should have a system where it is simply not possible to teach to the test," said Mr Brooks.
Tests were making it "very difficult" to deliver the kind of teaching that was "sensitive to individual pupils", he added.
In a statement, the General Teaching Council for England said: "We welcome the IPPR's report on assessment - it supports our view that the current regime encourages "teaching to the test" and that tests are being used for too many conflicting purposes.
"The GTC wants to see a reduction in the overload of testing and is proposing that samples of children are tested at the end of every key stage, to monitor national standards over time.
"We also back the IPPR's call for more trust to be placed in the professional judgement of teachers to use assessment to support pupil learning more effectively."
The Department for Education and Skills said tests were an integral part of effective teaching and learning and were "a non-negotiable part of school reform".
INSTITUTE FOR PUBLIC POLICY RESEARCH
founded in 1988
calls itself the UK's leading progressive think tank
close links with Labour Party
thinking underpinned many policies of the 1997 New Labour government
current director Nick Pearce was a special adviser to David Blunkett at the Home Office and education department
"They provide valuable objective evidence in the core subjects, helping inform further improvements to teaching and learning," a spokesman said.
"They are not designed to be 'pass or fail' examinations and we have stressed that preparation time should be kept to an absolute minimum and that teachers help children prepare best when they teach the core subjects as fully and effectively as possible."
The department said the Qualifications and Curriculum Authority monitored them to ensure they tested a depth of knowledge that could not simply be instilled by "teaching to the test".