Every January, educationalists - and many in the wider public - in Wales are sent into paroxysms of anger by the publication of a particular set of figures.
Once dismissed by policymakers in the devolved government, these statistics have become an acute source of embarrassment for the nation that supposedly models itself as the "learning country".
More than any other publication, the anonymous-sounding Local Authority Education Expenditure statistics reveal just how far the country's education system has distanced itself from that of its closest neighbour, England. And it's not in a good way.
In 1999-2000, the spending gap between the two nations was just #163;58 per pupil, a more-or-less negligible 2 per cent difference. The last set of figures revealed that in 2009-10, after a decade of devolution, the gap stood at #163;604 per pupil, a 10.8 per cent difference. No longer negligible, then. The latest figures will be published next Thursday, and educationalists wait with bated breath.
Results have also suffered correspondingly (see pages 28-29), and education is no longer a source of pride in the principality. In fact, it is the cause of deep-seated national soul-searching.
Since 1999, when the fledgling National Assembly was first given powers over education, Wales has sought to forge its own path.
From the abolition of secondary league tables and the scrapping of Sats tests to the revamping of curricula and the promise that free schools and academies would have no place in Wales, the country has been slowly but surely divorcing its school system from that of England.
But some of the early, well-intentioned decisions made by the Welsh government are now coming back to haunt it. Indeed, one senior Tory in the Westminster government has suggested - only slightly tongue in cheek - that Wales should be treated as a case study of what would happen if the NUT ran education policy. In other words, how not to run schools.
How has this happened? Why has it happened? And what lessons can be learned?
Theories are diverse, but David Reynolds, professor of educational effectiveness at the University of Southampton and a senior policy adviser to the Welsh government, calls it the "big brother" syndrome.
"It's the psychological situation of having your big brother living next door and trying to compete, which I think did Wales huge damage in the short term," he says.
"For much of the 2000s, Wales defined what it should do in terms of not doing what big brother does, and that was a huge mistake."
At Christmas, leading headteacher David Swallow retired from Barry Comprehensive School in the Vale of Glamorgan after almost 14 years at the helm.
Swallow's CV is impressive: he was awarded an OBE for his services to education in 2003 and under his leadership the boys' school, one of only two in the country, was named the most improved in Wales for three successive years.
In 1999, only 24 per cent of pupils gained five GCSEs at grades A*-C; this year, the figure was 70 per cent. Yet this remarkable success has been achieved despite the fact the school is very poorly funded, even by Welsh standards. The Vale of Glamorgan Council has the lowest budgeted expenditure per pupil in Wales at #163;4,901, a whopping #163;1,538 less than the highest spending, Ceredigion.
When he moved to Barry in 1998 from running a boys' school in Manchester, Swallow was surprised at the financial situation.
"Even in 1998, before devolution, England had so many more initiatives that enabled certain grants to get to schools," he says. "The difference in funding between Wales and England was a shock then and it's even more significant now. Funding on its own doesn't necessarily make all the difference, and it's not an excuse for poor results, but it is certainly part of the vehicle that will help you improve. That money could be very beneficial to help you move forward."
Swallow says that Wales has too many local authorities - 22 for a population of just over 3 million - and that they are too small to run their education services strategically.
A lack of subject specialists in the Vale council has forced Swallow's staff to buy in support and expertise from a local company.
Although he is positive about many of the Welsh government's curriculum developments, particularly the 14-19 Learning Pathways initiative and the Welsh Baccalaureate qualification, he envies the opportunities his English colleagues enjoy.
With a strong record in the performing arts, he could see Barry Comprehensive becoming a successful specialist school or academy, if only Wales offered such incentives. Instead, the government has promised to ban their introduction altogether.
But Swallow says he accepts the situation, even if he doesn't like it. "It's understandable that Wales was keen to be different and set its own agenda after devolution. It's inevitable that certain things would change."
The first and biggest dividing line between Wales and England was drawn in 2001 when secondary school league tables were scrapped after years of opposition from teachers and unions. They were "crude, divisive and misleading", the government said, and did nothing but name and shame failing schools.
But some educationalists, including senior government figures, thought the decision rash, and essentially "threw the baby out with the bathwater" because it led to a situation where data were not kept and effective comparisons between schools were no longer possible.
And last year, the move was called into question by a controversial report from the University of Bristol, which claimed that it had had a "sizeable" impact on results, equal to a drop of almost two GCSE grades per pupil per year.
Then, between 2002 and 2008, the deeply unpopular Sats tests for 11- and 14-year-olds were phased out and replaced by teacher-led classroom assessments.
The high-stakes tests were accused of putting pupils and teachers under too much pressure. But again, that decision was called into question by a report last year, this time from Welsh inspectorate Estyn, which said that the teacher assessments of 11-year-olds that replaced Sats are often inaccurate and unreliable. Inspectors found huge inconsistencies between individual primary schools and expressed concern over the lack of a national system to verify results.
But now, national testing of maths and reading and school ranking in the form of banding are both back on the cards after a "disastrous" set of results in the 2009 Programme for International Student Assessment (Pisa) tests that shocked the education system out of its complacency.
In the 2009 Pisa tests, run by the Organisation for Economic Cooperation and Development, Wales performed significantly worse than each of the other UK nations in all three measures (reading, maths and science) and worse than in the previous tests of 2006.
It prompted a bout of serious soul-searching, and education minister Leighton Andrews subsequently announced a programme of radical reforms to improve standards.
But - as with much relating to Pisa - this is perhaps a more nuanced subject than politicians would have you believe. Indeed, whether abandoning Sats had an impact on Wales' Pisa performance has been questioned by Andreas Schleicher, head of the indicators and analysis division at the OECD.
"It's a fine line ... You could say maybe England has had in the past too much high-stakes testing, too little formative assessment, and in Wales it's been perhaps the other way round. But clearly you need some benchmark for success and whether abandoning those kinds of assessments altogether was the right thing, that's really up for debate," he said in a recent interview.
"At the end of the day, teachers, students and parents need to know how they are progressing. You'll find very few education systems that do well without knowing how well the students have performed."
But in other measures, too, Wales seems to be slipping behind its neighbour. In October, it was revealed that 58.3 per cent of pupils in England gained five good GCSEs (grades A*-C) this year, including English and maths, compared with 49.6 per cent in Wales.
Although the Welsh government acknowledged the difference in the face of heavy criticism, it said that the results were not directly comparable because England's large independent school sector accounted for many of the top grades.
In Wales, fewer than 2 per cent of pupils are enrolled at independent schools, compared with just over 7 per cent in England.
Even the UK government admitted the improvement on last year's results in England was a consequence of the inclusion of statistics on the IGCSE maths qualification, taken in many independent schools.
As well as the raw data, the 2009 Pisa survey also included information from school and student questionnaires, which gives a more detailed picture of differences between the two education systems. Heads in Wales reported higher levels of resource shortages than England, but lower levels of staffing shortages.
Another international study sheds some light on how pupils in the two nations view their educational experience. The Health Behaviour in School-aged Children survey (HBSC) includes a number of questions on attitudes to school.
The results of the most recent survey have not yet been published, but the 2005-06 study reveals some interesting findings.
It seems that pupils in England enjoy their education more than their counterparts across Offa's Dyke, with a higher percentage of 11-, 13- and 15-year-olds saying that they like school a lot compared with those in Wales.
However, England also has the highest percentage of pupils in every age group who say they felt pressured by schoolwork. Wales also seems to have less-friendly pupils, with fewer 11- and 13-year-olds agreeing that their classmates are kind and helpful than those in England.
So what is each country doing right, and what can they learn from each other?
Neil Foden, headteacher of Ysgol Friars comprehensive in Bangor, says that, despite the recent gloom and doom, Wales has much to be proud of.
"Until relatively recently, Wales was better than England at listening to its teachers," he says. "It was also less inclined to do some of the socially divisive things that England has done, such as introducing academies and free schools.
"Scrapping league tables was good because they just encouraged schools to focus on improving their position in the tables, and not improving their offer to pupils."
He also points to the success of the foundation phase policy for 3- to 7-year-olds. Inspired by the Nordic education model, this formal curriculum is set aside in the early years in favour of a play-led approach, with children encouraged to learn through their actions and interactions with each other, both inside and outside the classroom.
Teachers in Wales are enthusiastic and excited about the policy, and appreciate the greater freedoms it gives them. They see the English equivalent, the foundation stage, as too prescriptive and target-led.
The skills-led Welsh Baccalaureate qualification is also considered a success. It complements GCSEs, A levels and vocational options, and aspires to a balance between skills and subject knowledge, with citizenship and community participation elements.
By comparison, its English equivalent, the 14-19 diploma, never really took off and support for it appears to have all but dried up. The controversial English Baccalaureate (EBac) is also nothing of the sort, but simply a performance measure based on a narrow range of qualifications.
In a state of flux
Brian Lightman was head of St Cyres comprehensive in Penarth before becoming general secretary of heads' union ASCL, so he has experience of both countries' education systems.
"The Welsh government is currently trying to put many new strategies in place to improve standards, like England did in the early 2000s. But the latter was underlined by huge investment and schools were funded to launch all kinds of interventions, which we see little evidence of in Wales," he says.
"In England in the past year we have had a massive change. Every single education policy is being completely altered. It's similar to the kind of change that Wales started in the early 2000s, but the difference is that the Welsh government was setting a vision. This (action in England) is stripping away all kinds of regulation and structures and leaving everything to individual schools to do.
"That has positives and negatives. At the moment, schools are in a complete state of flux and there's a serious risk of fragmentation of the system. But more positively, it has strengthened school leaders' attitudes to collaboration - more are working together and sharing services."
Perhaps the most realistic question to ask is whether we can fairly compare education between Wales and England any more, and should we even try?
Dylan Wiliam, emeritus professor of educational assessment at the Institute of Education, University of London, says it is possible, but with caveats.
"Any education system is always a response to a number of local forces," he says. "They are often trying to solve different problems and rarely make any sense from the outside."
And Reynolds of the University of Southampton says that any comparison based on public examination data is "verging on the dangerous", but he thinks comparisons are still possible.
"As I see it, the systems, because of their desires about education and economic growth, are singing from the same hymn sheet in terms of their goals and aspirations," he says. "However, they are differing more and more in terms of the processes they are using to reach those goals.
"Wales became so different throughout the 2000s, but the direction of change in the past year has been for England to spin off in very different ways in terms of processes and goals. For the next few years I would expect there to be wider divergence.
"England has moved from prescription to more freedom, while Wales has gone the other way. You cannot have freedom if you don't know how to exercise it. England has been resource- and capacity-building, but Wales did not do that; it gave teachers freedoms inappropriately. Autonomy works but you can only do it when you give people the capacity to do it.
"Wales is slowly realising that there needs to be a Welsh way forwards, which includes what England and other countries have done."
Wiliam says neither country has got it 100 per cent right, despite what they might think.
"I'm a firm believer that high stakes accountability testing can improve student achievement, but it has to be done much smarter than it is in England.
"There's probably not enough pressure on teachers and pupils to do well in Wales, and too much in England," he says. "Wales in particular has suffered by taking the pressure off teachers and schools. On the other hand, whether you would want the kind of pressure you have in England is another question. Pupils in England aren't happy."
David Bright, headteacher of Llantarnam comprehensive in Cwmbran, took up his first headship post in Wales on the cusp of devolution in 1999 after several years of teaching in England. He says that from the outset it was clear that the difference in funding and resources between the two nations was like "chalk and cheese", but the biggest difference was that Wales was more insular.
"We were looking at what the school down the road was doing instead of the best-performing schools in the UK or Europe," Bright says. "Increasingly, we were running our schools for the benefit of the people who worked in them instead of the people who attended them. The unions had a lot more influence in Cardiff Bay."
This, of course, chimes with the views of the Westminster Tories on what schools would be like if the NUT were in charge.
But Bright is insistent that union influence has had many positive benefits - teachers feel more respected and trusted to do their jobs. This has come at a price, he says: the "dilution" of performance management and school inspection, both of which are now being strengthened under the new regime.
He says that the "decade-long retreat" from high-stakes testing and accountability was coupled with a slew of well-meaning initiatives and a plethora of grants.
"There were too many initiatives and for years we struggled with priorities. Nobody ever measured the outcomes of all these schemes or the impact of the grants, so we don't know whether they even made any difference. At least now we are starting to get a sense of priority, and that can only be a good thing."
Given the radical pace of change in Wales' education system over the past decade, perhaps it's not surprising that policymakers are now reviewing their decisions, taking stock of the situation and slowing down the pace of change.
And maybe, just maybe, Welsh politicians are learning their lesson. Change for change's sake may not be the answer.
Indeed, education minister Andrews says he is more than happy for England to be the "laboratory" for educational experiments in future. Welsh schools will probably breathe a sigh of relief.
GO COMPARE: POLICIES ACROSS THE UK
The other two nations of the UK are going through their own educational dilemmas.
In Scotland, education has always been a distinct aspect of the national identity, a source of pride and something that sets it apart from the rest of the UK, particularly England.
But Walter Humes, visiting professor of education at the University of Stirling, says that educationalists north of Hadrian's Wall no longer compare their policies or achievements with those of the "old enemy".
"Politicians in recent years have tended to make comparisons with Nordic countries, particularly Finland," he says.
"The democratic outlook we like to think we have is better reflected in the Nordic countries than in England, which is seen as a more stratified and class-led society."
Humes says that Scotland has been served well by its system, but questions are starting to be asked about its future. "I think we are now at the point where we need to be asking whether this rather uniform system is serving us as well as it used to. In England, there is more diversity. I'm not saying it should take the same form as England, but we need to be more open-minded."
Northern Ireland, which although it follows the English curriculum and qualifications system still has grammar schools and 11-plus selection, also no longer feels the need to look across the Irish sea for inspiration.
Former secondary headteacher Professor Sir Robert Salisbury, who has been leading a literacy and numeracy review in Northern Ireland for the past four years, says: "Increasingly, there is an all-Ireland look at what works in education, because the Republic does very well in all sorts of areas.
"Educationalists here do look at what's happening in Scotland and they do look outwards to see what is happening in other countries, but they find it increasingly difficult to compare with what is happening in England."
On paper, Northern Ireland's GCSE results are usually the highest in the UK. This year, it again outperformed the other two nations, with 74.8 per cent of entrants gaining A*-C grades, compared with 69.8 per cent in England and 66.5 per cent in Wales.
But Salisbury says that the figures merely support the "enduring myth" that pupils in Northern Ireland perform better than those England and Wales, when it is actually the country's selective grammar school system that accounts for most of the top grades.
"The reality is that the top 5 per cent of pupils do well, but there is a very long tail of under-achievement, and at the bottom end, the results are poor," he says.
"There's almost been a sweeping under the carpet of poor achievement and accountability. Very little has been said about this."