Council leaders are calling for an independent review of Ofsted, amid concerns that the schools watchdog is losing credibility.
The inspectorate's objectivity and reliability has been brought into question in recent months, according to the Local Government Association (LGA), which said action is needed so that parents can have confidence in the system.
It claimed that Ofsted has a habit of re-inspecting schools and children's services when they have hit the headlines and often then downgrading them from a previous judgment, which sometimes may have only been handed out months before.
The LGA highlighted the "Trojan Horse" scandal - which related to an alleged plot by hardline Islamists to take over schools in Birmingham. This saw five schools downgraded to "inadequate", the lowest Ofsted category, in some cases only months after previously being inspected and given a higher rating, it said.
And Haringey Council's children's services were downgraded from "good" to "inadequate" after the Baby P scandal was made public in 2007.
Councillor David Simmonds, chairman of the LGA's children and young people board, said: "Mums and dads, when choosing a child's school, are making a commitment, and need to know that a judgment is credible. So when a judgment goes from the highest to the lowest rating in months, when results, leadership and management has been consistent, it leaves them in a confused position.
"They need to know whether Ofsted got it right the first time or the second time, but it can't be both."
The LGA said that serious problems and under-performance must be tackled, but insisted that there are questions about whether the inspectorate's judgments were accurate in the first place, as it is quick to re-inspect and often downgrade schools and services caught up in a controversy.
It said it is concerned that Ofsted seems to have become more focused on reacting to incidents in the public eye, rather than the experiences and outcomes of children and young people.
Mr Simmonds said: " Too many controversies have threatened Ofsted's independence and credibility. Mums and dads put their trust in Ofsted's ratings when they pick a school for their children and its inspections can have implications for the most vulnerable children in our care.
"Councils, communities and parents need to know Ofsted and the chief inspector are independent and free from political influence and we need an independent review to discover what has gone wrong and restore faith in what is fast becoming a media-driven organisation.
"In cases where we have seen schools go from outstanding to special measures within a few years, which verdict is to be believed? This is not a defence of under-performance; there is no place for it in our schools and children's services. Ofsted's knee-jerk response to a scandal seems to be to re-inspect a school and declare it failing, but not every scandal will be true. We want to know that when Ofsted go into a school, they are being fair and impartial and are not playing to the court of public opinion."
Russell Hobby, general secretary of the National Association of Head Teachers (NAHT), said: "Ofsted is not doing what it should, which is to get beneath the data and find out what is really happening in schools. Too often, overworked and under-skilled inspectors have time merely to confirm what the data already tells us, copy some narrative from a previous report and rush on to the next school.
"The LGA is right that a fundamental review is needed. Inspection should be about expert judgment and quality feedback which leads to improvement or the massive expenditure is wasted in what amounts to a public relations exercise."
An Ofsted spokesman said that the watchdog has "raised the inspection bar" for education and care services, including getting rid of the "satisfactory" rating, making "good" the minimum acceptable standard.
"This has galvanised those we inspect to improve, which is leading to better outcomes for children and young people," he said.
"Nearly eight in 10 schools are now judged by Ofsted to be good or outstanding. Hundreds of thousands more children are now benefiting from a decent education because of the challenge and support we have given to previously under-performing schools.
"But we also know that when you challenge the system to do better, it will push back.
"Of course, Ofsted is not perfect and we have been open about where we need to improve our own performance. We are currently consulting on radical changes to the way we inspect schools and colleges from next September as well as taking steps to bring all education inspectors in-house."
He added: "Ofsted's job is to hold every institution to account and to report without fear or favour. We make no apology for championing the interests of those who rely on the services we inspect nor for bringing our findings to wider public attention. Shining a spotlight on under-performance, however uncomfortable, helps bring about change.
"But it is simply incorrect to suggest our inspection judgments are influenced by anything other than the evidence we find. We know that previously high performing institutions can deteriorate rapidly when they suffer staff turbulence or a sudden change in leadership."
A Department of Education spokeswoman said: " Inspection by Ofsted is an important part of our accountability system, providing parents and the public with an independent assessment of the performance of schools. Ofsted keeps its inspection arrangements under constant review to ensure they are fit for purpose."