Defra

You are here: Home > Statistics > Food and farming statistics > Food > Family food > Family food methodology

Family food methodology

The following notes explain the background to the survey and detail the methods used.

  1. About Family Food - This note introduces the survey by explaining the history, data collection methods, available data and its main strengths.
  2. Sampling - The main factors that affect the reliability of the survey results are sampling variability, non-response bias and incorrect reporting of certain items of expenditure and income.  This note explains the sampling frame, the response rate and accuracy, and how non-response bias is corrected for using sample-based weighting and census population-based weighting.
  3. Trends and ticks - Quality assessments are included to make estimates of averages per person per week of expenditures and quantities of food purchases easier to interpret and use.  This note describes the method used to calculate the trend indicators, reliability ticks and significance of change that are published with many of the estimates.
  4. Free food and unspecified meals estimation - Some people receive free food, and there are different types of unspecified meals in the source data. This note includes definitions and describes how nutritional intakes from unspecified meals are estimated.
  5. Reference nutrient intakes - Family Food compares estimated nutrient intakes with guideline daily amounts. This note explains Reference Nutrient Intakes, Estimated Average Requirements and Dietary Reference Values along with how intakes are estimated.
  6. Adjustments to NFS - In 2001 the National Food Survey was merged with the Family Expenditure Survey to form the Expenditure and Food Survey, which was subsequently replaced by the current Living Costs and Food Survey.  This notes explains the adjustments that were made to the the historical data to make it comparable to the new survey methods.  The spreadsheet of the values derived using this method is available.
  7. Multiple Regression – The data presented in Chapter 4 of Family Food 2010 on demographic patterns in key dietary indicators was analysed using multiple regression. This document explains the methodology.
  8. Food and Drink Codes – Some types of food and drink have been grouped together within each of the categories in this report for ease of reference. This document lists foods that make up the food and drink types.

Downloads

13 December 2011

26 March 2011

Page last modified: December 13, 2011