The accelerated conversion of schools into academies has made “little difference” to pupil outcomes, according to economists.

A report from the LSE’s Centre for Economic Performance (CEP), ahead of next month’s general election, found that the expanded academies programme, rolled out by the coalition government in 2010, has “not been successful for the most part”.

This is true for both primary and secondary schools, the research suggests.

Related: Academies must justify high pay to get capital funding

Viewpoint: It’s time for the final stage of academisation reform

Ofsted: Curriculum ‘suffered’ because of academisation

The Conservative Party has pledged to “continue to build more free schools”, which are academies, in its election manifesto.

The report, which reflects on the state of the education system in the lead-up to the general election, found that it would be sensible for politicians to focus on the “recruitment and retention of high-quality teachers”, rather than “large-scale structural reform”.

“Unfortunately, the flagship academies policy has for the most part made little difference to overall pupil outcomes,” it says.

“Politicians of all parties have put too much faith in changing school structures. Unfortunately, the evidence suggests that such changes can be costly and do not always work.

“It is more important to address the reasons why schools underperform in the first place, such as lack of funding and, in particular, difficulty in recruiting and retaining good teachers.”

It also found that austerity is likely to have had “big detrimental effects” on the learning of young people, and the expansion of early years provision has, to date, “not been very successful” in improving child development.

The number of academies has soared since the “radical” expansion was rolled out by the Conservative-Liberal Democrat government at the beginning of the decade.

Currently, more than 70 per cent of secondary schools are academies, compared with just 3 per cent prior to 2010.

The report added: “Resources are not infinite and some of the education policies proposed by the political parties are unlikely to produce any beneficial effect on educational outcomes - these include further structural change (for example, more “academisation” or more free schools); roll-out of early years provision with no change in quality; and the abolition of tuition fees.

“These policies may be desirable (at least for some groups) for other reasons, but if funding was instead put into general school expenditure and improving teacher quality we would be likely to see positive effects on student outcomes.”

The Department for Education and the Conservative Party have been approached for comment.