Tarunesh Srikrishna, a graduate of the 2023 HSC, developed a curious habit when he was studying for his year 12 biology exam.

“During the HSC, one of my hobbies was to look at other states’ papers,” he said.

So when a friend forwarded the university student last Friday’s exam and he scanned the questions, it was not surprising that the exam looked familiar. He had seen essentially the same questions before.

There was the one about the fruit fly, the one about animals and air temperature, and the one about stopping the spread of Varroa mite among the bee population.

“I was like ‘Wait, where have I seen that before?’” Srikrishna said, and the answer was in the Western Australian Certificate of Education’s biology exams, 2019 to 2023.

A spokeswoman for the NSW Education Standards Authority, which is in charge of setting HSC exams, said similarity to other states’ questions was due to similar syllabuses. “We unequivocally dispute any suggestion that NSW’s Higher School Certificate uses exam questions from other jurisdictions,” she said.

However, in this case, specific air temperatures used in a scenario in one question had remained the same, while another data set in the same question had simply been increased by four degrees.

Srikrishna said: “There’s no way this is a coincidence. There’s no chance you made that up on your own.”

Over the weekend, he contacted the Herald with a summary of the similarities across the two papers.

“I just think HSC papers, they’re so high stakes, they should all be original. I don’t think they are copying from other states’ papers.

“I can accept that there is only so much content to assess in biology, and there are bound to be similarities between papers, but almost direct replications in terms of wording, answer options and data make this harder to palate.

“If students are held to high standards of academic honesty, surely the same should apply to the ones who write the exams. This raises serious questions about the equity and integrity in the HSC system.”

In one question, students were presented with the body temperature of an animal relative to changes in air temperature, ranging from 18.8 to 27.5 degrees.

Those air temperatures are identical to those in the 2022 West Australian exam.

Dr Simon Crook, who runs science education consultancy CrookED Science, said chances of those precise temperatures between 15 and 30 degrees, to one decimal point, in the same order had a statistical probability of one in more than 11 trillion.

“If they were smart about it, they could have just put in new numbers for the air temperature, but they couldn’t even do that,” he said.

“I think a lot of people will be really miffed. It is lazy. Here we have teachers who are underpaid and overworked, trying to do things properly. But something like this, teachers can live and die professionally by their HSC exam results and if some students are advantaged because some teacher gave them past WA questions, that’s grossly unfair.”

Knox Grammar’s head of science, Elizabeth Thrum, who has previously set HSC trial biology exams, said the year 12 biology for NSW and for Western Australia were both created in reference to the national curriculum.

“I can recognise there are some similarities in the phrasing, [but] it is the Australian curriculum we teach to, the questions that we ask are going to be very similar,” she said.

The NESA spokeswoman also cited the common curriculum and said, “it is not unusual for exam authorities to use the same or similar stimulus for exam questions”.

“NESA has rigorous processes in place to uphold the integrity and confidentiality of exams throughout the development and writing process,” she said.

“The questions in the 2025 NSW HSC Biology exam align to content examined in the NSW Biology syllabus, including concepts relating to genetics, mutations and diseases. These concepts are not unique to the NSW syllabus.”

Question 29 on the HSC paper asked students to “explain TWO procedures that could have been employed to prevent the spread of the Varroa mite in honey bees”.

Question 24 of the 2021 West Australian biology exam asked students to outline “two measures that could be used to reduce the chances of this mite becoming established in Australia”.

Tabitha Jimenez, HSC biology coordinator at tutoring firm Matrix Education, said questions about chromosomes in fruit flies were quite common and regarded as classic questions.

“Essentially, they have very similar sex chromosomes in humans, so they have an X and Y, and not all animals are like that,” she said.

However, she said others such as regarding Varroa mite in bees were not. “Question 29 is the one that I’m surprised how similar it is ... it’s kind of the same,” she said.