title: An investigation of the validity and reliability of a food intake questionnaire.
abstract: OBJECTIVE
  To evaluate the reliability and criterion validity of a food intake questionnaire (FIQ) designed for use in schoolchildren.
  
  
  METHODS
  Study of reliability: 98 young people aged 13-14 years attending two schools in deprived areas of Liverpool completed the FIQ on three separate occasions over a 3-month period. VALIDITY STUDY: Ninety-six young people (aged 11-13 years) completed the FIQ and 2 weeks later completed a 3-day food diary (with interview).
  
  
  RESULTS
  The FIQ gave consistent response on separate occasions over the 3-month reliability study period. Levels of agreement were consistent between survey combinations. Analysis of variance showed no differences in mean score for food groups between surveys. Pearson correlations for mean scores estimated by separate FIQ ranged from 0.42 for fibre food group to 0.76 for negative marker food group; the majority of the correlations were above 0.5. The data suggested the FIQ should be able to detect a change of +/-10% in eating habits. The validity study provided modest but significant Pearson correlations between energy intake, fat intake as a percentage of energy intake and sugars intake derived from 3-day diaries, and mean scores for the fatty, sugary and negative marker food group assessed by the FIQ.
  
  
  CONCLUSIONS
  The results from both studies provide an indication of the FIQ's reliability, and suggest it has criterion validity for fatty and sugary and negative marker foods.
authors.affiliation: Department of Community Nutrition and Dietetics, Abercromby Health Centre, Grove St., Liverpool L7 7HG, UK.
authors.forename: B
authors.initials: B
authors.lastname: Johnson
authors.forename: A
authors.initials: A
authors.lastname: Hackett
authors.forename: M
authors.initials: M
authors.lastname: Roundfield
authors.forename: A
authors.initials: A
authors.lastname: Coufopoulos
mesh_terms: D000293:Adolescent; D000704:Analysis of Variance; D002648:Child; D015930:Diet Records; D004435:Eating; D005260:Female; D006801:Humans; D008297:Male; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires; D006113:United Kingdom