By Angela Harrison
BBC News education reporter
The inspections cover a wide range of services
Most people, even those without children, know how schools are inspected in England.
Parents rely on Ofsted's reports when looking for schools for their children.
Teachers complain of the stress of having an inspector at the back of their class and head teachers of the mountain of data they have to supply and the grillings they face from inspectors.
But until the outcry over the death of Baby P and the failure of Haringey Council to protect him, it was not well known that Ofsted is also charged with ensuring that councils' child protection and other children's services are up to scratch.
It took over that responsibility in April 2007.
Now, everyone seems to know that Haringey Council children's services were rated "good" last year, shortly after Baby P died.
But what do inspectors look at to reach such conclusions?
In the case of schools, head teachers are given very short notice of an inspection - typically two days - before inspectors descend.
Under the new "light touch" inspections, Ofsted officials are with schools for just two days, watching lessons and talking to staff and pupils. They will have assessed published data - such as exam or test results - in advance.
Inspectors report on how good lessons are and analyse a detailed "self-evaluation" made by the school, which outlines what it sees as its strengths and weaknesses.
The reliance on information provided by the body being inspected is common to the systems for schools and children's services, and calls have been made for more checks to be carried out.
But what is involved in an inspection of a council's wide-ranging children's services?
The details published on Wednesday - giving a rating of children's services across the country - relate to annual assessments which are purely desk-based.
No field work is carried out. Officials carrying out what is known as an Annual Performance Assessment look at documents and data to see if a council has made progress in the previous 12 months "towards improving outcomes for children and young people".
They look at "a wide range of published evidence" which indicates how good councils are at helping and safe-guarding children and young people.
This will involve data on schools, including attendance and anti-bullying policies, the attainment of children in care, young offending, the infant mortality rate, child protection, proportion of young people not in work or training and teenage pregnancy rates.
Inspectors meet the council's senior managers to discuss "issues that may have arisen during the analysis of information".
They rely on the local authorities to provide accurate information.
Local authorities are then graded for their children's services, in the same way as schools are - from inadequate at the bottom, to adequate, good and finally outstanding.
They are judged on the following criteria:
- Overall effectiveness of children's services
- Being healthy
- Staying safe
- Enjoying and achieving
- Making a positive contribution
- Achieving economic well-being
- Capacity to improve services for children
Ofsted faced criticism for this arm's length form of assessment and has announced it will be replaced with another next year which will have a "stronger focus on frontline practice", including annual unannounced inspection visits in every local authority.
MPs were critical of the inspection regime last week when Ofsted's head Christine Gilbert appeared before them at the commons' children, schools and families committee.
Committee chairman Barry Sheerman said there were "real concerns" about Ofsted's inspection practices. He called for an inspector to be placed in every local authority.
On top of the annual, desk-based assessment, all councils have faced one full, personal inspection of children's services in the past three years.
This is known as a Joint Area Review (Jar) and involves inspectors talking to front-line workers as well as children, parents, senior managers and elected council members.
Inspectors will stay with a council for a few weeks and their number - and their amount of field work - will depend on how well a council is understood to be performing. Ofsted says this approach is about being "proportionate to risk".
Inspectors also select at random case files relating to some of the most vulnerable children in an area to see how far services are working together in an area to help them.
At the end, they rate the children's services on a scale of one to four in the following areas:
- Looked after children
- Children with learning difficulties
- Service management
- Council's capacity to improve