Out-of-field teaching in mathematics at Year 10 in New South Wales: evidence from PISA 2015

"Out-of-field" teaching in mathematics refers to teachers who teach the subject without mathematics-specific qualifications to do so. Out-of-field teaching has the potential to affect teachers' classroom instruction practices with consequences for student learning. This report describes the incidence and correlates of out-of-field teaching of Year 10 mathematics in New South Wales, the most populous state in Australia, relative to the rest of Australia. We draw on Australian PISA 2015 data to examine the prevalence of out-of-field teaching in relation to different teacher and school contexts. We found the qualifications profile of teachers teaching mathematics in New South Wales was different from the rest of Australia. In New South Wales 28% of Year 10 teachers were qualified to teach mathematics; 21% had one, and 79% at least two subject specialisations (corresponding proportions outside New South Wales were 34%, 6%, 94%). Yet only 19% of teachers taught Year 10 mathematics in New South Wales, with an out-of-field teaching rate of 20% (outside New South Wales the respective proportions were 16% and 19%). This suggests the co-existence of out-of-field teaching with an apparent excess supply of mathematics teachers in some schools and their potential under-utilisation. Outside New South Wales, out-of-field mathematics teaching was higher in low economic, social and cultural status (ESCS) schools with resultant cumulative disadvantage for these students In New South Wales, out-of-field teaching rates in mathematics were significantly lower for teachers who were in schools with a high (≥ 25%) versus low (< 25%) concentration of students who spoke another language than English at home, reflecting the choices recent 'aspirational' migrant parents make in relation to selective government schools that admit students based on academic abilities. These schools tend to concentrate students from high socioeconomic background and have relatively more resources available, such that they have less difficulty attracting qualified teachers. The effect of so many selective schools in New South Wales has created a two-tier division in the public school system. A key challenge for public policy is to more equitably distribute qualified teachers of mathematics to reduce the concentration of out-of-field mathematics teaching for less resourced schools in this two-tier system.