Year 12 students at one of the state's top-ranked selective schools will need to resit a major chemistry assessment after they were given an identical paper to that used four years ago, which had already been used for preparation by many students.
Students at Baulkham Hills High School who sat their chemistry half-yearly exam last month will resit the test on Thursday, less than two weeks before the start of trial HSC exams, after about one-third of the cohort got full marks.
It is understood many students and tutoring services had access to the past paper and used it to prepare for the test, prompting complaints from students and parents to the school, the NSW Department of Education and local MP David Elliott.
"As soon as it became aware of the issue, the school began mapping out the most equitable solution to ensure that no student was disadvantaged as a result of a school mistake," a spokeswoman for the NSW Department of Education said.
"It was determined the only fair option would be to give no weighting to the initial exam and have all students complete a new exam assessment.
"Counselling is available to all students and the school is developing new safeguards to ensure this doesn’t occur again."
Half-yearly exams make up between 15 and 30 per cent of the internal school assessment mark for the HSC at most schools.
Schools submit raw internal assessment marks to the NSW Education Standards Authority, which moderates these against the school group's performance in that subject's external HSC exam by student rank and mean.
The student with the highest raw internal mark gets a moderated internal mark that is equal to the highest external HSC mark achieved by a student at the same school, and the internal mean is adjusted to be the same as the group's external mean.
Internal tests that give an unfair advantage to some students can significantly skew moderated assessment marks, by affecting students' rank.
The school's principal apologised to parents for use of the past paper at a P&C meeting on Tuesday, and confirmed students would resit the test this week, a parent told the Herald.
Year 12 half-yearly exams at the school were scheduled at the end of term two, between June 25 and 29. Students returned for term three after school holidays on Tuesday and will begin trial HSC exams on August 6.
This year's HSC exams begin on October 18.
A spokesman for Mr Elliott said he spoke to staff at NESA, which administers the HSC, about the issue after receiving complaints from parents.
"If the [issue is raised again] we'll make representations to the relevant minister, the Minister for Education," the spokesman said.
Baulkham Hills High School was ranked second in NSW in last year's HSC, with its students achieving 778 high scores.
Five students from the school achieved the highest possible ATAR of 99.95 last year, and 72 per cent of year 12 students got an ATAR above 95.
Chemistry was the most popular HSC science subject at the school last year and was taken by 123 year 12 students.
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