League tables can mislead parents trying to make comparisons between schools, say researchers.

A report funded by the Office for Standards in Education says that performance tables fail to show which schools make the most progress with their pupils.

According to the report's author, Professor Harvey Goldstein of the Institute of Education in London, league table rankings "largely reflect schools' intakes" and say little about how much pupils improve while at the school.

As such, parents trying to use league table rankings to compare schools will not receive a "reliable picture" of the quality of teaching and could draw "misleading conclusions".

The research also explored whether the league tables could be made more equitable by including factors such as the social background and gender of pupils.

But even with such factors taken into account, the researchers still claimed that the league tables could not adequately distinguish between successful schools and those which were simply benefiting from the social advantages of their intake.

The research examined the league table placings of primary schools in Hampshire, in an attempt to see what Ofsted inspectors could interpret from the annually published league tables.

The researchers have concluded that the tables fail to indicate the degree of progress achieved by schools - information which they believe would be of use to inspectors, parents and the schools themselves.

League tables are based on the test results of 11-year-olds and researchers say that this fails to show how much of an impact schools have made on the 'raw material' of their intake.

Professor Goldstein says that the report, The Use of Value Added Information in Judging School Performance, raises important questions about the type of information used to measure school achievement.