The latest school league tables are often the first port of call for parents in England when choosing schools - but what do they measure and how reliable are they as a gauge of school quality?
What is in the tables?
The tables measure school performance data. This is statistical information showing how well pupils in England have done in public examinations taken at key points during their school careers.
At primary level, these are the national curriculum tests, or Sats, taken in Year 6 at the age of 10 or 11.
While for secondary schools, the statistics detail pupils' performance in GCSEs (and equivalent exams) at age 15 or 16 and A-levels (and equivalents) at age 17 and 18.
Haven't the primary Sats exams changed recently?
Yes, there was a big change to the tests four years ago. Primary pupils who took Sats in summer 2016 were the first to sit more rigorous papers with a different grading system.
Until 2015, Sats tests were graded on levels - for example Level 4 was the expected level for children finishing primary school.
Now parents are given their child's raw scores (the marks they get) and told whether or not they are at the expected level.
The reading and maths test scores are given on a scale of 80 to 120 - with a score of 100 or more meaning a pupil is meeting the expected standard.
Writing is assessed by the children's own teachers, who have to decide whether individual pupils are meeting or exceeding the expected standard.
What about secondary schools?
Secondary performance used to be judged mainly on what proportion of pupils gained at least five GCSEs above a C grade, including maths and English.
But that changed in 2016, with two new measures, known as Attainment 8 and Progress 8, introduced.
Attainment 8 measures pupils grades across eight key subjects, while Progress 8 assesses their progress compared with what was expected of them based on their Sats test scores at the end of primary school. Schools are given a score based on how their pupils have progressed compared with the national average.
The secondary school league tables are published in January.
How is the performance data presented?
The Department for Education publishes the data, with a facility on its website allowing users to rank schools in England by different measures.
What happens in the rest of the UK?
Wales and Northern Ireland abolished the publication of school league tables in 2001, followed by Scotland in 2003.
However, in 2017, data about how well Scottish pupils do in reading, writing and numeracy was published for the first time, as part of the new Curriculum for Excellence.
Wales reintroduced the publication of performance information in 2015, with schools colour-coded - green, yellow, amber or red, in a bid to raise standards.
Are the tables useful?
The league tables are often the first port of call for parents who want to choose schools for their children or simply judge how well schools in their area are doing.
Ministers say the tables help drive up standards by providing valuable information for parents and increasing local accountability.
And research carried out by Bristol University suggested the abolition of league tables in Wales in 2001 had led to a drop in standards in about three-quarters of schools.
But many education experts say comparing schools in this way is too crude a measure of a school's quality, achievements and character.
They argue that the tables often say more about the intake of a school than the teaching and learning that goes on there.
Critics also say the tables encourage competition, rather than collaboration, between schools in local areas and can lead to middle-class parents pushing to get their children into top schools, further driving down standards at less popular schools.
There are also suggestions that children are pushed into subjects and choices that make the school look good, rather than broadening their education.
Should I choose a school for my child based on league tables?
The tables show how well a particular year group of pupils at a given school has performed in tests or exams.
But they will not tell you anything about the extra-curricular activities on offer such as sport and drama or details about a school's pastoral care system.
Some of these details may feature in the school's Ofsted report, but there is no substitute for visiting a school you are interested in, or talking to teachers, parents and current pupils.