Mr Blunkett said that there were significant differences between schools with high numbers of pupils entitled to free school meals.

BBC: You are in: Education

However, it should be noted that differences between some schools might be slight.

ECONOMIST: Which MBA? rankings

The differences between these two schools of thought are large and evident: for dualists, the informal economy is marginal, residual and comprises those who are most disadvantaged, while for voluntarists, it is a much more complex sector with context-specific dynamics and numerous connections and implications in terms of formality and regulation.

FORBES: Informality: A Marker Of Opportunity

The census of the school workforce, taken in November 2012, reveals differences in pay between academy schools and those schools still under local authority control.

BBC: Hundreds of school leaders paid in excess of ?100k

One of the most obvious differences between American and international business schools is the cost and duration of the MBA program.

FORBES: The Rise of the International MBA

One recent analysis had to discard 75% of its research because it had failed to account for differences between the backgrounds and academic histories of pupils attending the schools.

ECONOMIST: Education

And, surprising as it may seem, the growing educational disparity between rich and poor schools cannot be traced to differences in spending.

ECONOMIST: America��s education choice