National Child Measurement Programme, England - 2017/18 School Year [PAS]

The BMI classification of each child is derived by calculating the child’s BMI centile and classifying as shown in the diagram below. This calculation uses age and sex as well as height and weight to take into account different growth patterns in boys and girls at different ages.

The NCMP uses the British 1990 growth reference (UK90) to define the BMI classifications.  This approach is recommended by The National Institute for Health and Care Excellence (NICE).

The prevalence of children in a BMI classification is calculated by dividing the number of children in that BMI classification by the total number of children and multiplying the result by 100.

Geographical analyses in this report are primarily based on the postcode of the child’s home address which is mapped to a lower super output area.  Some time series analyses use the school postcode as the child postcode was poorly populated in the early years of the NCMP and these are labelled in the report.

^{1. The BMI classification “Severely obese” is a subset of “Obese". Children with a BMI centile of between 95 and 100 are classified as “Obese” and those with a BMI centile of between 99.6 and 100 are classified as “Severely obese". For more information: See annex B}