In the past decade, the Welsh education system has twice received a wake-up call in the form of poor results in the Programme for International Student Assessment (Pisa) tests. The last set of results, published by the Organisation for Economic Cooperation and Development (OECD) in 2010, showed that 15-year-olds in Wales were performing significantly worse than their counterparts in the rest of the UK in maths, reading and science.

The results prompted Welsh education minister Leighton Andrews to launch a raft of reforms, with the aim of climbing the rankings. But now, just months after students sat the latest round of Pisa tests, the Welsh government has again invited the OECD to review the quality of education in the country.

The government hopes that the review, which will focus on 3-16 education and will report in March 2014, will provide it with expert analysis of education policy and whether its reforms are working. Mr Andrews said it was important that Wales understood its strengths and weaknesses on the global stage if it was to deliver for pupils.

Critics have accused the minister of being “obsessed” with Pisa and the OECD and have attacked the cost of the exercise, which will run to hundreds of thousands of pounds.

“Rather than admitting that the improvement agenda is in crisis, the minister has called for yet another review,” said Rex Phillips, Wales organiser of the NASUWT teaching union.

“Given that the minister’s track record on use or misuse of OECD data to support his agenda for change is well established, we would want to see the terms of reference for this review to be satisfied that it will be fair and even-handed, and we need to be given assurances that he will not cherry- pick the findings to support his vision for the Welsh edu- cation system.”

But Professor David Reynolds, a senior government policy adviser, said that the move would bring “world-leading experts” to the country. “The experience of countries that have done this in the past has nearly always been positive,” he said.

Michael Davidson, a senior OECD analyst responsible for Pisa, told TES that a final agreement with the Welsh government would be signed within a few weeks. Although a price has yet to be agreed, Mr Davidson admitted that the cost of the exercise would run to hundreds of thousands of pounds.

Mr Davidson said that the OECD already had a picture of the education system in Wales based on previous Pisa results and other published data. “In terms of average performance, the picture for Wales is pretty bleak,” he said. “It’s not clear why 15-year-olds in Wales should be performing at a lower level than those in the rest of the UK.

“It’s still the case in Wales, as in many other countries, that social background is a significant determinant of educational success.

“The biggest challenge within Wales’ education system is within the four walls of a school - the variation in performance within schools rather than between schools.”

Although the review will look at Mr Andrews’ 20-point action plan in more detail, Mr Davidson said the improvement agenda seemed to be following a “sensible approach”.

“Some of the action points - including professional development for teachers, improving school leadership, focusing on literacy and numeracy - are all important policies for any education system to get right,” he said.

Scotland invited the OECD to review its skills strategy in 2007 and subsequently saw improved results in the 2009 Pisa tests.

“I don’t think the Welsh education system has anything to be afraid or ashamed of,” said Professor Reynolds. “The review is not free but on the other hand it’s not expensive. You get a lot of bang for your buck.”

How the review will work

The OECD will ask the Welsh government to prepare a background report on its education system and current policy reforms within the next few months.

This will be used to guide the organisation’s review team of between five and six people, including external education experts, who will pay a week-long visit to Wales later this year.

However, the team will wait until the 2012 Pisa results are revealed in December 2013 before publishing their findings in 2014.