The data for this measure is taken from the Active Lives (AL) Survey in 2015/16 and 2016/17.
Respondents to the survey were asked 2 questions about how many portions of fruit and vegetables they eat on a usual day. Respondents were counted as eating 5 portions of fruit and vegetables on a usual day (‘5-a-day’) if their responses on the numbers of fruit and vegetables added up to 5 or more.
The survey sample is randomly selected from the Royal Mail’s Postal Address File, which has a very high coverage of private residential addresses. A letter is sent to households inviting up to 2 people per household to take part in the survey, either online or by requesting a paper version of the questionnaire. A random sampling survey design ensures results are representative of the population. Results for 2016/17 are based on responses from a sample of around 198,250 people. Only people aged 16 or older were included.
Weighting is used to adjust the results of a survey to make them representative of the population and improve their accuracy.
For example, a survey which contains 25% women and 75% men will not accurately reflect the views of the general population, which we know has an even 50/50 split.
Statisticians rebalance or ‘weight’ the survey results to more accurately represent the general population. This helps to make them more reliable.
Data has been weighted to ONS population measures for geography and key demographics.
The confidence intervals for each ethnic group are available if you download the data.
57.4% of adults surveyed in 2016/17 reported eating 5 or more portions of fruit and vegetables on a usual day (‘5-a-day’). This is a reliable estimate of the percentage of adults in England who ate ‘5-a-day’, but because the AL Survey results are based on a random sample of adults aged 16 or older, it is not possible to be 100% certain of the true percentage.
It’s 95% certain, however, that somewhere between 57.2% and 57.7% of all adults in England ate ‘5-a-day’ in 2016/17. In statistical terms, this is a 95% confidence interval. This means that if 100 random samples were taken, then 95 times out of 100 the estimate would fall in this range (i.e. between the upper and lower confidence interval). But 5 times out of 100 it would fall outside this range.
The smaller the survey sample, the more uncertain the estimate and the wider the confidence interval. For example, the number of people from the Chinese ethnic group sampled for this survey is relatively small compared with the entire population, so we can be less certain about the estimate for the smaller group. This greater uncertainty for people from the Chinese ethnic group is expressed by the wider confidence interval of between 48.0% and 54.1%.
Statistically significant findings have been determined where the 95% confidence intervals of an ethnic group do not overlap when comparing with another ethnic group or between time periods
The Wilson Score method for calculating confidence intervals has been used. This gives very accurate confidence intervals for proportions and odds based on the assumption of a binomial distribution. The Wilson Score method is the preferred method for calculating confidence intervals for proportions.
For further details of the sampling method and weighting see the Active Lives Survey technical report.
Figures have been rounded to 1 decimal point in the charts and tables. Unrounded figures are available if you download the data.Quality and methodology information