"The effect will be long-term and may cost us dearly."
That was the assessment of Wanganui High School principal Garry Olver on his school this week being regraded under the decile rating system.
The high school was one of a number in the Wanganui district that have been advised of changes to their decile ratings. For some it means a loss of funding, for others an increase.
Wanganui High School, currently a decile 5 school, has been re-graded to decile 4.
"This has a positive and negative effect," Mr Olver said.
"On the positive side, it will mean approximately $34,000 added to our 2015 budget, and when money is tight every cent helps - especially in the light of the education ministry's circular which discourages parents from paying towards the 'voluntary' costs of providing a first-class education.
"On the negative side, the lower decile rating is likely to have a marked effect on our recruitment of international fee-paying students.
"We currently have 77 international students and the effect will be long-term and may cost us dearly."
Mr Olver said the public perception of decile rating linked to academic performance lay at the heart of the issue.
"Unfortunately, we are the most exceptional example of how this generalisation is incorrect."
Mr Olver said Wanganui High School was the highest performing decile 5 New Zealand state co-educational secondary school.
"Our academic results are better than many of the most prestigious decile 10 co-ed schools.
"Our 2013 dux, Matthew Standley, was the fifth highest achieving premier scholar in New Zealand.
"We are the only decile 5 school in history to be both Confucius Classroom and Cambridge International examinations accredited."
Cullinane College's decile rating will change from 3 to 4 which means an increase in funding although principal Kevin Shore said it would have a negative impact on other things such as health services.
"It means we will have fewer visits from the public health nurse and it reduces the principal's salary - although I'm not worried about that.
"We don't think about it most of the time, we are focussed on mapping students' academic achievement."
Aramoho School with a role of just 35 students will move from decile 1 to 2.
"It will mean a decrease of around $4500 a year for us and that is quite a lot for a school this size," said principal Deb Griffiths.
"Thankfully it won't affect other provisions because a decile 2 school is still deemed to have higher needs in terms of health and social supports for students."
Wanganui Girls' College principal Tania King said the school's current 3h rating would change to 3i and she doesn't think it would make much difference.
"It will mean a small decrease in our funding but it won't affect us otherwise."
Brunswick school principal Jan Clark said there has been no change to the school's decile 7 rating.
"The status quo is good I suppose - we don't get more money but at least we don't lose any."
Wanganui Principals' Association chairman and principal of St Anne's School Karl Zimmerman said the decile ratings were a funding mechanism and nothing more.
"The system is overdue for review and, as the Education Minister has said, it is a blunt instrument that was introduced almost 20 years ago.
"I won't be surprised if a review has taken place before the current decile changes are implemented."
Decile ratings were introduced in 1995 and they measure the wealth - or lack of it - from a school's catchment area.
Using census figures, the ratings are based on averages for the school area such as household incomes, parents' occupations and education, household crowding and whether the family has received income support during the past year.
Each decile contains approximately 10 per cent of schools and decile 1 schools are those with the highest proportion of students from low socio-economic communities.
Decile 10, the highest level, are the schools with the smallest number of students from low socio-economic backgrounds.
Education minister Hekia Parata has called the system well-intentioned but also "really clumsy".
"There are some significantly disadvantaged kids and families in deciles seven, eight, nine and 10 schools, but overall the average masks that," she said.
She has asked Ministry of Education staff to explore new options and expects them to report back in around two months time.
NZEI president Judith Nowotarski said that funding to all public primary schools had been decreasing and that should be addressed before there was any change to the decile rating system.
"Regardless of decile, all schools struggle to stretch their funding to meet the needs of all students, and funding needs to increase across the board."
Most schools have now been advised as to whether their decile ratings will change and all schools will be advised before the end of November.