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The Ministry of Education cited the factors as possible reasons the scores of New Zealand's 15-year-olds in the OECD's Programme for International Student Assessment had not improved.
The scores were slightly worse than in the previous round of testing in 2015, but the ministry said the differences were not statistically significant.
However, it said it was worried by the long-term trend of declining scores and the latest figures were equivalent of three-quarters of a year's education lower than scores recorded last decade.
Secondary Principals Association president Deidre Shea said schools were certainly seeing more challenging students than in the past but it was not because schools lacked discipline.
She said they are wrestling with the impact of wider problems such as teenagers' general well-being and family incomes.
"Those are well-understood and will have negative impacts in terms of young people being able to concentrate in class, being ready to learn and all those sorts of things," she said.
Michael Johnston, the associate dean (academic) of Victoria University's School of Education, said classroom disruption could be partly to blame for New Zealand's position and he believed the teaching of reading in primary schools also needed more attention.
"I know that they're talking about the classroom environment and bullying and things like that. All of things could be factors. I'd also want to have a look more deeply at the pedagogy itself. How are we teaching children to read and is that working, I think there's some questions to be asked there," Dr Johnston said.
A senior researcher at the Council for Educational Research, Cathy Wylie, said there were plenty of programmes aimed at improving the teaching of maths, reading and science but they needed to be supported and applied more consistently across all schools.
"The right things, they're there, but they're actually a bit piecemeal," she said.
"I think what we've still got is a lot of pocketed stuff and until you start to join up the dots - a strong curriculum centre within the Ministry of Education, really good local support, good national and local networks of teachers and some really good frameworks that people can be working with rather than having to invent the wheel at every school for every teacher, I don't think you're going to get the substantial shift," Dr Wylie said.
She said many of those changes would happen as a result of the recommendations of the Tomorrow's Schools Review taskforce, which she was a member of.
However, she said it would take a long time for New Zealand's PISA results to improve.
"Substantial change will take a few years to come about and it will need ongoing, concerted attention and I don't really think we'll see much change in these PISA results for another six to nine years."