NCMP 2007/08 frequently asked questions
Based on the questions we are asked the most we compiled these frequently asked questions
- What is the National Child Measurement Programme?
- Why are these data being collected?
- Who participated?
- What are the main findings?
- Where can I view the results?
- Does this mean that obesity is increasing?
- How were the children measured?
- What do we mean by overweight and obese?
- Which are the areas with the worst obesity problem?
- Which areas have the lowest obesity levels?
- Is obesity worse in boys or girls?
- How do the results for obesity differ between Year 6 and Reception?
- The NCMP also took place in the 2005/06 school year. Why haven't you included data from this year in the report?
- Do the figures relate to England or the UK?
- Can we compare with other countries?
- Was it compulsory for children to participate in the programme?
- We know that only 88 per cent of eligible children were measured. How do we know these results are meaningful?
- If PCTs could add or remove schools and alter numbers of children in each school, doesn't this mean that they could lower the numbers to make it look like they've measured a greater percentage than they really have?
- Which PCTs have the highest and lowest child obesity prevalence?
- How was the NCMP data collected?
- What is the NCMP data collection tool?
- How do we know that all organisations maintain the security of the information? The role of the PCT.
- How do we know that all organisations maintain the security of the information? The role of The NHS Information Centre.
- How do I view the results?
- How can I print off the results?
1. What is the National Child Measurement Programme?
Established in 2005, the National Child Measurement Programme weighs and measures primary school children aged 4- 5 (reception) and 10 -11 (year 6).
The programme has been produced using one of the largest databases of its kind in the world.
2.Why are these data being collected?
The National Child Measurement Programme was set up in line with the Government's strategy to tackle obesity and to:
- inform local planning and delivery of services for children
- gather population-level data to allow analysis of trends in growth patterns and obesity
- increase public and professional understanding of weight issues in children and be a vehicle for engaging with children and families about healthy lifestyles and weight issues.
For 2007/08, 88 percent (973,073) of all eligible pupils from Reception (aged 4-5) and Year 6 (aged 10-11) were measured, an increase of 8 percentage points from 2006/07.
The school children involved were from state maintained primary schools in England. PCTs were encouraged, but not obliged, to include independent schools and special schools in their NCMP measurements.
4. What are the main findings?
In Reception, almost one in four of the children measured in 2007/08 was either overweight or obese. In Year 6, this rate was nearly one in three;
- in Reception, between 2006/07 and 2007/08, there has been little or no change in the prevalence of underweight, overweight and obese children
- in Year 6, there was no significant change in the prevalence of underweight, overweight and obese children between 2006/07 and 2007/08.
The percentage of obese children showed an apparent increase of 0.8 percentage points between 2006/07 and 2007/08; however, much or all of this increase is likely to be due to the increased participation rate for Year 6 between the two years - the percentage of children who are obese is almost twice as high in Year 6 than in Reception
- the percentage of children who are overweight is only slightly higher in Year 6 than in Reception
- the overall percentage of children who are underweight is similar for both years. Differences between boys and girls were significant but very small for both years;
- obesity prevalence is significantly higher than the national average in the North East, West Midlands and London SHAs for both age-groups as well as North West SHA for Reception children and Yorkshire and Humber SHA for Year 6 children
- obesity prevalence is significantly below the national average in the South East Coast, South Central, South West and East Midlands SHAs for children in both school years, as well as for Year 6 children in the East of England SHA
- the 2007/08 SHA obesity patterns are similar to those observed in the 2006/07 NCMP
- obesity prevalence is significantly higher in urban areas than in rural areas, as was the case in NCMP 2006/07
- as in the 2006/07 NCMP findings, a strong positive relationship exists between deprivation and obesity prevalence for children in reception and Year 6.
5. Where can I view the results?
See the full report:
Read the report which summarises the key findings from 2007/08. Where possible, comparisons have also been made with the 2006/07 NCMP results.
NCMP data tables View the national, SHA and PCT data tables.
6. Does this mean obesity is increasing?
Between 2006/07 and 2007/08, there has been little or no change in the prevalence of obese children in either school year.
However, we would recommend that at least five years of data will be essential before any trends over time can be detected and confirmed.
7. How were the children measured?
Measurement of children's heights and weights, without shoes and coats and in normal, light, indoor clothing, was overseen by healthcare professionals and undertaken in school by trained staff.
8.What do we mean by overweight and obese?
To work out if an adult is overweight or obese is pretty straightforward. If they have a BMI of 25 to 29.9, they are considered overweight, and if they have a BMI of 30 or more, they are considered to be obese.
To work out if a child is overweight or obese is more complicated. Since children's height and weight change at different rates at different ages it is not possible to use simple BMI cut-off points, as used with adults, to decide whether they are overweight or obese.
Instead, a complex adjustment has to be made to children's BMI, and this adjusted figure has to be compared to other information about how children grow at different ages in order to tell if they are overweight or obese. Different adjustments have to be made for boys and girls, and the adjustments are different at different ages.
In accordance with NICE guidelines, we apply the “Cole's LMS Method” to standardise children's BMI using the national standardised growth charts. A child can be defined as “overweight” and “obese” by looking at their standardised BMI (“p-score”):
- where this is less than the 2nd percentile, they are considered to be underweight
- where this is between the 85th and 95th percentile, they are considered to be overweight
- where it is greater than the 95th percentile they are considered to be obese.
- Further detail can be found in the report or by referring to Cole's LMS Method: “Growth monitoring with the British 1990 growth reference. Cole Arch Dis Child.1997; 76: 47-49”.
9. Which are the areas with the worst obesity problem?
Obesity prevalence is significantly higher than the national average in the North East, West Midlands and London SHAs for both age-groups as well as North West SHA for reception children and Yorkshire and Humber SHA for Year 6 children.
10. Which areas have the lowest obesity levels?
Obesity prevalence is significantly below the national average in the South East Coast, South Central, South West and East Midlands SHAs for children in both school years, as well as for Year 6 children in the East of England SHA.
11. Is obesity worse in boys or girls?
The prevalence of obesity is significantly higher in boys than in girls in both age groups.
Back to top12. How do the results for obesity differ between Year 6 and Reception?
The percentage of children who are obese is almost twice as high in Year 6 (18.3 per cent) than in reception (9.6 per cent).
13. The NCMP also took place in the 2005/06 school year. Why haven't you included data from this year in the report?
In 2005/06, less than half the eligible children (48 per cent) were measured. Because there is so much missing data in the 2005/06 dataset, it is not considered to be robust enough for comparisons to subsequent years.
14. Do the figures relate to England or the UK?
The report looks at children in England only.
15. Can we compare with other countries?
Different countries use different methods for defining overweight and obese children. International comparisons would be very difficult and are outside of the scope of this report.
16. Was it compulsory for children to participate in the programme?
Participation in the programme was not compulsory, but non-participation was on an opt-out basis only.
Before the programme started, PCTs wrote to the parents and carers of all children eligible for measurement to inform them of the work and to give them the opportunity to opt their children out.
Children were not made to participate if they did not want to.
17. We know that only 88 percent of eligible children were measured. How do we know these results are meaningful?
Annex 6 of the report investigates whether results could have been biased through not including measurements from the missing pupils, and looks at the possible effect of participation rate on the reported prevalence of overweight and obese children.
We carried out statistical analysis and concluded that a lower participation rate may lead to an underestimation of prevalence of overweight / obese children for Year 6.
However, given that the participation rate increased between 2006/07 and 2007/08, this level of potential ‘bias' in the Year 6 result is decreasing over time.
Participation rate is shown to have little or no effect on prevalence for reception children.
18. If PCTs could add or remove schools and alter numbers of children in each school, doesn't this mean that they could lower the numbers to make it look like they've measured a greater percentage than they really have?
The NHS IC performed a number of validation checks on the data to ensure that the findings were as accurate as they could be.
If, for example, one PCT removed a school from its results but the school was not subsequently recorded by another PCT, the school was added back in to the original PCT's list.
The overall figures on numbers of eligible pupils provided by PCTs were compared with those provided by DCSF, and any variations were queried by The NHS IC and agreed with the relevant PCT where necessary.
19. Which PCTs have the highest and lowest child obesity prevalence?
Although 88 percent of all suitable children's weights and heights are recorded as part of the NCMP 12 percent of children within England are not measured. This means that we can not be certain about the exact obesity prevalence for all children in a particular PCT area.
When comparing obesity prevalence across different areas, it is necessary to consider the element of uncertainty - or the 'confidence intervals' - around the estimates.
A confidence interval is a range of values within which we can be certain, with a particular level of confidence, that the true value for the population will lie.
Where confidence intervals overlap for two areas, it is not possible to say that the obesity prevalence is higher or lower in one area than in the other.
It is therefore not possible to sort PCTs according to their child obesity prevalence in a meaningful way.
Data collection and security
20. How were the NCMP data collected?
Primary Care Trusts (PCTs) collected data on children's height and weight from the schools within their area.
The data were submitted to The NHS Information Centre using the NCMP data collection tool and all of the returns were collated and validated centrally.
21. What is the NCMP data collection tool?
The IC collected the data using the NCMP Data Collection tool, which has led to the creation of one of the largest databases of its kind in the world. Populating this data warehouse involved:
- the development of a secure data collection tool and supporting secure data warehouse
- storing anonymised data relating to children's height, weight and location
- generating aggregate information data for geographically defined populations other than school catchments areas.
The NCMP data collection tool comprised of three elements:
- the development of a Microsoft Excel based tool to capture the necessary variables on-site, with inbuilt validation of data to maximise the potential of collecting robust and accurate data including a feedback of summary data
- a web site to enable NHS Primary Care Trusts to securely submit data to The IC and to view a data quality report on the data that they have uploaded
- the development of a data warehouse to capture and analyse the captured data.
22. How do we know that all organisations maintain the security of the information?
Every year the Department of Health and the Department for Children, Schools and Families provide guidance to PCTs and schools which emphasises how to undertake the exercise. The guidance also clearly points out that:
- the privacy and dignity of the child must be safeguarded at all times and the measurement is to be done sensitively in a private setting;
- the height and weight information must be gathered by health professionals with minimal physical contact; and
- PCTs will take steps to ensure that parents receive a letter explaining the purpose of the programme, and provide them with the opportunity to withdraw their child from it.
23. How do we know that all organisations maintain the security of the information?
The NCMP data capture tool is held securely by The NHS IC. Guidance leaflets for all staff which promote the NHS IC's compliance with Data Protection and Information Security are available and can be requested from The NHS IC Contact Centre on 0845 3006046 (www.ic.nhs.uk).
- although The NHS IC will not have access to any patient identifiable information, there are robust information security measurements in place to ensure that data is held and accessed securely
- before loading the data electronically, the measurement process is overseen by trained healthcare professionals and is not shared with school staff or pupils.
PCTs upload the data electronically to the National Child Measurement Database, developed and maintained by The NHS Information Centre for health and social care - when the data is uploaded to the NCMP database the data is anonymised by removing or converting all identifiable data: the name of the child is automatically removed; the postcode is converted to lower Super Output Area; the date of birth is converted to age in months
- individual children's results will not be shared with school staff or other pupils and suppression and disclosure controls will be implemented when the dataset and publication is released.
When data is published, small numbers that could allow individual children to be identified will be suppressed. - local authorities and other delivery partners are given an anonymous, aggregated report only, and do not have access to the raw data.
Any organisation wishing to obtain access to the anonymous national dataset requires the approval from both The NHS Information Centre and the Department of Heath.
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