Changes to the National Child Measurement Programme 2020-21 methodology and publication content

The National Child Measurement Programme (NCMP) measures the height and weight of children in England annually and provides data on both the number and proportion of children in reception and year 6 who are underweight, healthy weight, overweight, obese and severely obese. This is the Body Mass Index (BMI) Classification. Data is collected primarily in mainstream state-maintained schools. Between 2010/11 and 2018/19 the proportion of children measured was over 90%. See Appendix A.

The collection period for schools to measure their children for the 2020/21 statistical publication would have run for the full academic year - September 2020 to July 2021. The coronavirus (COVID-19) pandemic disrupted this. In late March 2021, when schools had reopened after being closed to most pupils since early January, local authorities were asked by the Office for Health Improvement and Disparities (formerly Public Health England) to use the remainder of the academic year to collect child measurement data in a sample of schools. This would enable a national estimate of children’s weight status (including obesity prevalence) for 2020/21 to be made.

The sample size was 10% of children in the local area. It was constructed via a selection of schools and designed to be representative of England in terms of deprivation and ethnicity mix of pupils.

Some local authorities measured in more schools than they were required to.

Statistical weighting has been applied to the data to ensure the sample is reflective of the population measured by NCMP in England in previous years. Details of this will be in the Methodology and Data Quality section of the publication. National figures are broadly comparable to earlier years because of this statistical weighting.

The volume of data collected was lower than in previous years. Prevalence estimates of the proportion of children who are underweight, healthy weight, overweight, obese and severely obese have been produced for reception and year 6 in England with breakdowns by sex, ethnic group, region, and Index of Multiple Deprivation deciles. The confidence intervals around these estimates are slightly wider than for earlier years.

Prevalence estimates have not been produced for local authorities

For enquiries about this please quote NCMP in the subject title of any correspondence via email to [email protected] or telephone 0300 303 5678.