Students who felt their teachers had high expectations of them did better in NAPLAN and were at least three months ahead of their peers by year 9, according to a new report that shows a teacher's encouragement to work hard drives academic performance.

The report also said that when two students had identical socioeconomic status and academic performance, a student who did not skip lessons in year 7 was on average three months ahead in their learning by year 9, compared with a student who had poor attendance.

The student with good attendance would also score almost five points higher in their year 9 NAPLAN reading test than a student who regularly missed school or turned up late.

Using data from the NSW Tell Them From Me student surveys in 2013 and 2015, the report looked at how students' engagement, performance and experience of classroom practices in year 7 affected their engagement and performance in year 9.