Measures
- Rate of teachers leaving the state-funded sector (attrition rate)
The number of full-time equivalent (FTE) teachers absent from the School Workforce Census (SWC) having been present in the previous census, presented as a proportion of the number of FTE teachers present in the previous census.
Attrition rates reported may differ from data reported by the Department for Education (DfE) due to methodological differences when cleaning the SWC data. Furthermore, attrition rates reported by the DfE account for only teachers with qualified teacher status (QTS), whereas we include both teachers with and without QTS.
Full-time equivalency adjusts every teacher in the census to the equivalent of a full-time teacher. For example, a part-time teacher who works 50% of a standard year would be classed as a 0.5 FTE teacher.
- Rate of early-career teachers leaving the state-funded sector (attrition rate)
The number of FTE early-career teachers (defined here as within five years of qualifying as a teacher), absent from the SWC having been present in the previous census, as a proportion of the number of FTE early-career teachers present in the previous census.
- Rate of teachers leaving their school (turnover)
The number of FTE teachers that are absent from the SWC or working in a different school, as a proportion of the number of FTE teachers present in the previous census.
Note: As outlined above, attrition and turnover rates are calculated using data for two academic years. In this dashboard, the rates are reported for the second academic year, by which the teachers will have the left the system or the school. For example, the 2023/24 attrition rate describes how many teachers who were in the census in 2022/23 had left the sector by 2023/24. In some other reporting, this rate is described as the 2022/23 attrition rate.
- Number of vacancies and temporarily filled posts per 100 teachering posts
The number of teacher vacancies (recorded as open when the SWC is collected in November) and the number of temporarily-filled teaching posts, as a proportion of the number of teaching posts (teachers plus vacancies) present in the census, adjusted to be expressed as a rate per 100 posts.
- Average expenditure per pupil on supply teaching
School-level reported expenditure on supply teaching, including spending on directly employed supply staff, agency staff and supply staff insurance (categories E02, E10 and E26), divided by the number of pupils.
Note: This data covers financial years. For example, 2023 covers the financial year between April 2023 to March 2024. At the time of preparing the data, school expenditure data for 2023 was not yet available, so this has not been included.
- Number of teacher trainees per 100 teachers
Number of trainees enrolled in initial teacher training providers based in the area, divided by the number of teachers employed in schools in the same area and adjusted to per 100 teachers. This measure does not capture trainees who are trained at a provider based in a particular area, but that may contribute to supplying other areas with new teachers.
- Number of trainees recruited to initial teacher training, as a proportion of the target
Number of trainees enrolled in initial teacher training programmes, as a proportion of the target required to meet the demand for new teachers (national only).
- Proportion of hours taught by teachers with a relevant qualification
Number of hours of key stage 3-5 subject curriculum time taught by teachers with a relevant post A level qualification in that subject, as a proportion of the total number of hours of key stage 3-5 subject curriculum time.
‘Relevant qualification’ is defined in the same way as the DfE qualification subject mapping (see Qualification subject mapping). We count non-teaching undergraduate degrees, Bachelor of Education and Postgraduate Certificates in Education qualifications as ‘relevant qualifications’ in the teaching of those subjects.
The DfE did not collect the qualification data in November 2020, due to reducing the administrative burden on schools during the pandemic, so these statistics are omitted for the 2020/21 academic year.
Note: These statistics (and those immediately below) may differ from measures as reported by DfE. Firstly, DfE include more qualifications in their list of relevant post A level qualifications than those included here, which are listed above. Secondly, since not all secondary schools provide curriculum data, the DfE uses a weighting methodology to adjust the measures that use curriculum data, whereas we do not. Thirdly, DfE and NFER may have made different methodological decisions made when cleaning SWC data.
- Proportion of science hours taught by teachers with different qualification specialisms
Number of hours of key stage 3-5 science (physics, chemistry, biology or general science) curriculum time taught by teachers with a relevant post A level qualification in physics, chemistry, or biology, or no relevant science qualification, as a proportion of the total number of hours of key stage 3-5 science curriculum time.
'Relevant qualifications' and subjects are defined as above for ‘Proportion of hours taught by teachers with a relevant qualification’. Please note figures may not sum to 100% across qualification subjects because it is possible for a teacher to hold a qualification in different scientific disciplines, in which case they would be counted more than once.
Adjustment made to subject-level measures
We made adjustments to the measurement method for some measures at subject level, to account for the number of hours taught per subject rather than FTE. Therefore, the following slightly different definitions apply to the subject-level analysis:
- Rate of teachers leaving the state-funded sector (attrition rate) at the subject-level
The total number of hours taught for the given subject by teachers absent from the SWC having been present in the previous census, presented as a proportion of the total number of hours taught for the given subject by teachers present in the previous census. - Rate of early-career teachers leaving the state-funded sector (attrition rate) at the subject-level
The total number of hours taught for the given subject by early-career teachers (within five years of qualifying as a teacher), absent from the SWC having been present in the previous census, as a proportion of the total number of hours taught for the given subject by early-career teachers present in the previous census. - Rate of teachers leaving their school (turnover) at the subject-level
The total number of hours taught for the given subject by teachers that are absent from the SWC or working in a different school, as a proportion of the total number of hours taught for the given subject by teachers present in the previous census.
In the SWC, a significant proportion of science teachers are identified as teaching combined science. These combined science hours are apportioned between the three component subjects based on the number of ‘known’ hours for the three subjects i.e. if 30% of the total hours taught in Biology, Chemistry and Physics is taught in Physics, then 30% of the total combined Science hours are attributed to Physics. This adjustment is used to calculate the attrition and turnover measures for the three component sciences. This has been defined using the same approach used by DfE in previous statistical analysis using the SWC (see DfE published: Analysis of teacher supply, retention and mobility). The ‘All Science’ subject includes combined science.
The subject-level national average measures are based only on the sample of teachers for whom curriculum data is present.
Area definitions
Areas are applied to all schools in all years, even if the data predates the boundary. For example, the 2024 parliamentary constituencies are used in all years. Boundaries have been simplified in the map so the dashboard loads quickly. To assign schools to area, we either used DfE information directly or granular geographic information.
- Local authority district areas.
Local administrative areas, as defined in April 2023. - Travel to work areas (TTWAs)TTWAs are a geography created to approximate local labour market areas: self-contained areas in which most people both live and work. The criteria for defining TTWAs are that at least 75% of the area's resident workforce work in the area and at least 75% of the people who work in the area also live in the area. The 2011 TTWAs were produced by Newcastle University, using an algorithm to identify commuting patterns from 2011 Census data. Some TTWAs overlap with country borders (e.g. England and Wales), but the teacher workforce data shown is only for the schools in England. More information on TTWAs is available on the ONS website.
- Parliamentary constituencies.
Electoral areas used for elections to the UK parliament. The areas are based on the areas used to elect MPs in the July 2024 election. - Teaching school hub (TSH) areas.
Teaching School Hubs are school-led centres of excellence focused on professional development for teachers. Each hub covers its own geographic area, which are used here. The areas are consistent with the hubs that came into effect in September 2024. Some hubs cover more than one area; where this is the case we have treated each area separately. More information on TSHs here.
School type definitions
Pupil deprivation (eligibility for free school meals)
We categorise schools into five equal-sized groups according to the proportion of pupils eligible for free school meals in the January School Census for each year. These categories are defined separately for primary and secondary schools.
Education investment area
Education investment areas are local authority areas that have been identified by Government analysis as being areas where pupil outcomes at the end of both key stage 2 (KS2) and key stage 4 (KS4) are lowest. The areas were identified as part of the Government’s approach to ‘levelling up’, in order to target school improvement interventions in the parts of the country where performance at primary and secondary school is furthest behind. The details of the methodology for selecting these areas is outlined here.
Type of geographical area
We categorise travel to work areas (see above) into five area types for analysis. The groups are defined as follows:
- London
the London travel to work area (which includes some areas outside of London boroughs).
- Large urban areas
travel to work areas, excluding London, with a working population (as of 2016) of more than 500,000 people. This group includes areas such as Manchester, Birmingham, Slough and Heathrow, and Hull.
- Medium sized areas
travel to work areas with a working population of between 500,000 and 150,000 people. This group includes areas such as Swindon, Blackpool, Scunthorpe, and Shrewsbury.
- Small, non-coastal areas
travel to work areas with a working population of fewer than 150,000 people, and that are not next to the coast. This group includes areas such as Taunton, Worksop and Retford, Darlington, and Penrith.
- Small, coastal areas
travel to work areas with a working population of fewer than 150,000 people, and that contain an area of coastline. This group includes areas such as: Isle of Wight, Hartlepool, Carlisle, and Penzance.