An expert on school league tables says introducing the system here would lead to schools narrowing their teaching focus, competing for the "best" students and rejecting those who fall behind in order to reach national targets.

Professor Martin Thrupp, of Waikato University, spent six years in Britain researching education markets and accountability in schools.

"People love to see the numbers - which schools are doing better - but within schools, there's a lot of anxiety."

Prime Minister John Key said this week that he would not rule out the Ministry of Education creating tables based on data from the National Standards policy.


But he added: "What I don't want to see is schools actually damaged by the information being presented in the wrong way."

Professor Thrupp said that is exactly what would happen. His research showed a competitive nature developed between schools and the focus soon turned to reaching national targets.

"Schools begin to say no to students - children with disabilities, children with difficulties in learning, children who come from poorer backgrounds.

"There becomes a national standards economy - a way of thinking where they narrow their teaching focus to just reaching those targets."

NZ Principals' Federation president Paul Drummond said he had attended a head teachers' conference in Britain where the issue was discussed.

"The morale is very low there. It's not popular at all and it's demoralising."

Mr Drummond said "naming and shaming" schools that would be dubbed the worst in the country was another big issue overseas.

"No matter how good the system is, the league tables have to have a top and a bottom. Imagine being a student or even teacher from the worst school in the country. [League tables] are only good for sport, not children."


NZ Educational Institute president Ian Leckie said international evidence on the effect of league tables on quality education was "damning".

Mr Leckie said league tables would ultimately change what Kiwi children would be learning and how they would be taught at school.

"League tables lead to a narrowing of the curriculum and a consequent loss of creativity and individual learning."