The way the Department for Education measures teachers' workload is not fit for purpose, an expert has warned.
Professor John Jerrim, professor of education and social statistics at the UCL Institute of Education, criticised the government's teacher workload survey, saying it has a woeful response rate and is “being done on the cheap”.
He has called on the DfE to commit more resources into gathering data on the hours teachers work from a truly representative cross-section of the profession.
And he warned that without these changes the government will be unable to check whether its efforts to cut teacher workload are working.
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Mr Jerrim is the lead author on a report out this week, which found that one in four teachers works more than 60 hours a week.
In a new post on the FFT Education Datalab site published today, he said that the "combination of low response rates and error in measurement has led me to conclude that the teacher workload survey (TWS), as it is currently designed, is not fit for purpose. It needs to change.
“The gold standard would be for the next workload survey to attempt to gather time-use diary data from a truly representative cross-section of teachers.
"This will undoubtedly mean that the DfE has to commit more resource to measuring teacher workload, rather than trying to do it on the cheap.
“Indeed, unless such data are collected, the DfE will probably never be able to measure teachers’ working hours with the necessary precision to determine whether their efforts to reduce teacher workload have succeeded.”
He said that for the data to be reliable the survey should include a large enough sample of teachers to minimise uncertainty through sampling error, it should also be randomly selected, have a high response rate and there should be as little scope for “measurement error” as possible.
Mr Jerrim described the response rate of the TWS as woeful. His post adds: “Out of the 900 schools initially selected (for the 2016 TWS), just 245 (27 per cent) agreed to take part.
“Then, of the 10,410 teachers within these schools, just 3,186 (31 per cent) completed the survey.
“The final overall response rate can then be calculated by multiplying these two percentages together (27 per cent multiplied by 31 per cent). This gives a figure of just 8 per cent.
“Or, put another way, out of every 12 teachers who were meant to respond to the TWS, 11 didn’t."
Mr Jerrim also raised concerns about the questions used in the TWS, but added: “It’s also worth saying that, whichever way you look at it, teachers in this country are working long hours”
A Department for Education spokesperson said: "We designed the Teacher Workload Survey with the profession, including teacher unions and practitioners, to ensure it is representative of the national population of teachers, and in a way that it does not put an extra burden on teachers when they take part.
“We will continue to review the ways we carry out research in this area to ensure data is reflective of the workforce.”
Mr Jerrim was the lead author in research led by University College London (UCL), published yesterday, which shows that teachers work around 47 hours per week on average during term time. Funded by the Nuffield Foundation, the research looks at data from more than 40,000 primary and secondary teachers in England collected between 1992 and 2017.