Call for school changes in Wales as GCSE data published
Calls have been made for a shake-up of how schools are run in Wales as variations are revealed in GCSE results between schools with similar backgrounds.
Conservatives and an experienced school inspector questioned the role of local education authorities (LEAs) in administering schools.
The Welsh Local Government Association called LEAs "cost effective".
Leighton Andrews called for a "school banding system".
The Welsh Government places schools in "families" - groups of about 10 - where pupils have similar levels of family income and special needs.
In one case a school's results are 42% better than another in the same family, a BBC Wales freedom of information request revealed.
The Welsh Government has dismissed the tables as "extremely simplistic".
Kirsty Williams, Leader of the Welsh Liberal Democrats said parents should have "the right to access information about the performance of their child's school" to ensure they are reaching theit potential.
She added it was sometimes "difficult and unfair" to compare schools across the country.
"League tables have rightly been criticised in the past for not giving an accurate picture of the overall performance of the school and the standard of its teaching. What parents ultimately what to know is: 'is my child's school improving?'," she said.
Plaid Cymru AM Simon Thomas said the party "does not believe that it is inevitable or acceptable for some schools to be good and some schools to be bad," adding that the Welsh Government "must take action" to ensure that pupils do not leave school unable to read, write or count.
"Plaid has made the case for a radical overhaul of the education system in order to get education right for all children, in all areas of Wales," he said.
Mr Thomas added that Labour plans to reintroduce school league tables "could mask the reality of underperformance and further undermine underperforming schools".
"It is not for parents through competition to improve schools but government and LEAs through action and direction," said Mr Thomas.
Conservative AM Angela Burns said the performance figures were "no real surprise", although league tables had to be treated carefully.
She is calling for local education authorities (LEAs) which administer schools, to be removed from the funding process.
"We would directly fund the schools, we would cut out the middle man, we would cut out the LEAs," she said.
"I'm quite sure they're not wildly pleased about that but it's a fact.
"When I was chair of the finance committee in the last term of the assembly, we did a number of reports on foundation phase, we did one on school grants that go into schools throughout the whole of Wales.
"The amount of money that gets sucked in by all of these people taking slices of this money...
"If you were to directly fund them [schools] from the Welsh Government... and give them a very clear set of outcomes that they had to achieve with that money, you would actually have proper money going where it is needed."
School inspector Gwynoro Jones said schools in Wales should be administered by four education boards rather than LEAs.
"It [school performance data] tells us what we've all known for a long, long time, but unfortunately it has been brushed under the carpet for various reasons," he said.
"There are significant variances in performance of pupils in schools in Wales, a wide range of variation in relation to the performance of teachers, head teachers, local authorities.
"The system and everything within it needs an entirely new revamp.
"We've known about this - leaders in Wales, education ministers, the union leaders - we've all known it but there's been a failure to tackle it.
"But I have to say I'm quite encouraged by how [Education Minister] Leighton Andrews is starting his new role and I'm relying a great deal on his leadership on this."
Mr Andrews hopes head teachers and governors will set ambitious targets for school improvement based on their performance against other similar schools.
He has said there is "systemic failure" in the school system and accused teachers of "complacency in the classroom".
In a speech in February, he suggested the Welsh government had its own plans to make some of this information public.
The body that represents councils in Wales, the Welsh Local Government Association (WLGA), said the best way to improve schools was to have better teachers and better support.
Steve Thomas, WLGA chief executive, said schools were a difficult service to run, but LEAs were cost effective and they worked.
"I find the Conservative proposals very interesting because what they are basically saying is that you can improve schools by cutting them by between 12% and 20% [in funding] and you can offset that by abolishing LEAs," he said.
"So making people redundant in LEAs costs nothing ,does it?
"And that would mean you have to run everything from Cardiff then."
He said abolishing LEAs would mean the assembly would have to carry out tasks such as consultations on school closures, running school transport and looking after special educational needs.
"We will be delegating 85% of our budgets down to schools. Some schools are complaining about that - they don't want to be purchasing these services," he added.
The Welsh Government has said it continues to oppose the publishing of league tables.
Chris Keates, general secretary of the NASUWT teachers' union, said: "The publication of these league tables is a reckless and irresponsible exercise.
"Schools which were 'top of the league' in the first list on Friday were languishing way down the second list by Monday morning.
"The information is not worth the paper its written on. However, it will have done untold damage to the morale and motivation of teachers and the confidence of parents in their child's school."
Following Friday's publication of schools' value added scores, it means BBC Wales has now made more information available on school performance than at any time since league tables were abolished in Wales in 2001.