TTR0072

Written evidence submitted by Doctor Shqiponja Telhaj, University of Sussex

Teacher Turnover: Effects, mechanisms and Organisational Responses

Introduction

Teacher turnover has been a perennial concern for policymakers but also parents. Teachers changing schools can have potential benefits because it is the mechanism by which teachers gain a variety of experience, new ideas and talents are brought into schools, and productive teacher-school matches are formed. However, there are also potential costs for students and schools when teachers move or leave the education system completely: this is because leavers take school-specific knowledge and experience with them, new arrivals may need extra training, they take time to assimilate and to gain much needed school-specific human capital, and there are also administrative costs imposed by turnover.

It is well documented that teacher turnover has been high for a long time in the UK. However, we know very little about what matters most: whether teacher turnover matters for student learning or other future outcomes. The overall presumption amongst policymakers is that teacher turnover has, on average, an adverse impact on student performance. This is because schools with high teacher turnover tend to do less well in terms of their student academic achievements than other schools. Turnover of teachers is also a perennial concern for parents, particularly when it occurs during the period when students are studying for important exams. However, despite the popular importance of this issue, there are relatively very few quality studies that investigate it empirically. Moreover, there are even fewer studies that investigate the potential channels through which turnover may be disruptive or examine organisational responses to mitigate potential negative effects of turnover. The lack of quality data has made the task of investigating turnover and performance in education, and more generally in the public sector, challenging.

Our research

Our study (Gibbons, Scrutinio and Telhaj (2021)) is, to the best of our knowledge, the first one in the UK that examines the direct causal impact of teacher turnover on student academic attainment, but also investigates the channels through which turnover can be disruptive for student learning. Our analysis of teacher turnover is based on a unique secondary school dataset that links the teacher workforce in England to students’ achievement and their characteristics’ records, by school and teaching subject categories, over five cohorts, between 2008/09 – 2012/13 academic years. We consider secondary school students in their last year of compulsory schooling (Year 11), and teachers in state-maintained secondary schools in England. We focus on GCSE educational outcomes of students by subject. Previous research has shown that performing poorly in GCSEs has long-lasting consequences on students’ careers (Machin et al. 2020), both in terms of further education and in early job outcomes. 

Impact of teacher turnover on pupil performance

Our first key finding is that students in the final year of their compulsory secondary education score less well in their final assessments if they are exposed to higher rates of teacher entry in the subjects they are studying. Entry in Year 11 seems crucially important. A 10-percentage point increase in entry rates reducing scores in final qualifications by 0.5 per cent of a standard deviation. This is not a huge effect, but it is non-negligible compared to many school interventions and the magnitude is similar to the effects of other turnover-related externalities in schools. The magnitude is smaller than the effect of turnover of students in schools (Gibbons and Telhaj 2011, etc.).

Impact on different groups of pupils

We found that teacher turnover appears to be less disruptive for disadvantaged students in the school - about one fourth lower. This suggests that schools may take actions to mitigate the disruptive effects for disadvantaged students by keeping newcomers away from this type of students. In addition, the negative effects of turnover seem to be larger for students in the middle of the ability distribution, proxied by their grade in the KS2 examination. We found that turnover has no differential effect on students’ performance regardless of the school student ethnic composition.

How turnover affects student attainment

In our research, for the first time, we also shed light on the potential mechanisms through which turnover can be detrimental to student learning and performance. We found that it is new teachers’ lack of school-specific human capital that matters (i.e. the lack of specific knowledge about the school the teacher is joining and its students). This lack of school-specific experience in incoming teachers is short term, however, and it disappears after the first year. Other potential causes, such as changes in teacher quality, teaching experience, or other teacher characteristics, do not seem to play a role. 

The impact of new teachers on pupil performance is almost exactly the same as that found in schools in the US, suggesting that effects are quite generalisable. One caveat here is that the English system is one with a standardised National Curriculum, which may make it easier for teachers to switch schools, and dampen the disruptive effects of turnover relative to a system where the syllabus is school specific. Then again, there are multiple exam boards (OCR, Edexcel, WJEC, AQA) which set assessments and define the exact syllabus. Different schools will often use different exam boards for different subjects, so teachers will still need to adapt to the specific syllabus they are required to teach, as well as adapt to the school-specific working environment.

School responses to mitigate the negative impact of turnover

We found that schools respond to mitigate the negative effects of turnover.by the way they organise teaching, implying that our estimates potentially underestimate the causal impact in a situation where new teachers were randomly assigned to students. Our findings indicate that schools keep new teachers, especially if they are new to the profession, away from teaching students in their final compulsory school year (new teachers are 13 percentage points less likely to teach in Year 11 than incumbent teachers). Even when they do teach this year group, newcomers have a lower teaching load and spend fewer hours teaching Year 11 students - with about 0.402 fewer hours per week than incumbents (the baseline for incumbents is 3.9 hours per week). New teachers also teach fewer hours per week overall (in all year groups): about 1.102 hours less than incumbents who spend about 14.5 hours teaching per week in the classroom. This may be to give new teachers time to adapt to the new school environment, and acquire the school specific human capital that is important for school performance. This is in line with the findings of “staffing to the test policies” studies.

Survey evidence suggests that exams and pressure to improve scores are among the major stress cause for teachers, which makes it less likely that teachers’ preferences are the driving factor behind the observed assignment pattern.

We found that schools that are classified as ‘good quality’, by OFSTED inspections, and especially those with ‘very good managers’ as concluded by OFSTED, are less likely to make newcomers teach and their students are less affected by turnover. This suggests that good schools have plans in place to respond better to disruptive effect of turnover.

However, it is clear that turnover of teachers matters regardless of these organisational responses. This indicates that new teachers result in an unavoidable general disruption as a result of the lack of school-specific human capital.

Conclusion

Our results show that schools can effectively reduce the impact of turnover through strategic reassignment of teachers by keeping new teachers away from teaching high-stakes to allow time to adapt and acquire the school-specific human capital. These findings might be useful for other public sector institutions, where turnover is pervasive.

References:

“Teacher turnover: Effects, mechanisms and organisational responses”, 2021, Labour Economics, 73, (with S. Gibbons and V. Scrutinio)

“Pupil mobility and school disruption”, 2011, Journal of Public Economics, 95 (9-10). pp. 1156-1167. ISSN 0047-2727, (with Steve Gibbons)

Machin, S., McNally, S., and Ruiz-Valenzuela, J. (2020). Entry through the narrow door: the costs of just failing high stakes exams. Journal of Public Economics, 190:104224

April 2023