They said that they were not impressed by the website which was fraught with several technical problems when it went online last Thursday.

Camden High School principal John Jarvis said information on his school's report card was incorrect and it was a farce the school was being compared to a selective high school.

The website uses the National Assessment Program Literacy and Numeracy (NAPLAN) test results of students in years3, 5, 7 and 9 to compare one school's performance with that of ``similar'' schools.

Mr Jarvis complained to federal Education Minister Julia Gillard late last year when he learned the information collected was incorrect.

``Last year we had 244 year 9 students sit the NAPLAN test but the results [on the website] are based on just 183,'' he said.

``That's crazy. We have a lot of good students who missed out on being counted.

``The reason given to me when I questioned this was the computers that scan the test booklets had not picked up on all of them.''

Mr Jarvis said it was unjust to place Camden High School in the same statistical group as Penrith High School.

``We have an Intellectually Mild Unit and, naturally, these students will struggle with literacy and numeracy and yet we're being compared to Penrith High School which is totally selective.

``I want accurate data and meaningful comparisons.

``I would like to see a fair system and that means my school with an IM unit is compared to another school with an IM unit, like Picton High School.''

Elizabeth Macarthur High School principal Justina Barnier said the website ``unfairly judges schools in a negative way''.

``Schools are so much more than data,'' she said.

Currans Hill principal Keith Wray said he was concerned the data gave a ``snapshot of the school that's not a very accurate one''.

He said NAPLAN results were a useful diagnostic tool for teachers but that it was unfair to use the results to compare schools. ``The people who aren't part of the school community don't know all that happens in the school and won't get that information from the website,'' he said. ``I'm concerned about how the information will be used.''