title: Test-retest reliability and construct validity of the DOiT (Dutch Obesity Intervention in Teenagers) questionnaire: measuring energy balance-related behaviours in Dutch adolescents.
abstract: OBJECTIVE
  Adequate assessment of energy balance-related behaviours in adolescents is essential to develop and evaluate effective obesity prevention programmes. The present study examined the test-retest reliability and construct validity of a questionnaire assessing energy balance-related behaviours in adolescents during the evaluation of the DOiT (Dutch Obesity Intervention in Teenagers) intervention.
  
  
  METHODS
  To assess test-retest reliability, adolescents filled in the questionnaire twice (n 111). To assess construct validity, the results from the first test were compared with data collected in a personal cognitive interview (n 20, independent from the reliability study). For both reliability and validity, intraclass correlation coefficients for continuous data or Cohen's kappa coefficients for categorical data were calculated as well as percentage agreement.
  
  
  METHODS
  Data were collected during school time from February to May 2010.
  
  
  METHODS
  Study participants were Dutch adolescents aged 12-14 years attending pre-vocational secondary schools.
  
  
  RESULTS
  In more than three-quarters of the ninety-five questionnaire items the test-retest reliability appeared to be good to excellent. Moderate reliability was found for all other twenty-one items. Fifty-one items (of ninety-five items) showed good to excellent construct validity. Construct validity appeared moderate in twenty-three items and poor in twenty-one items. Most items with poor construct validity concerned consumption of sugar-containing beverages and high-energy snacks/sweets.
  
  
  CONCLUSIONS
  Our study showed good test-retest reliability and largely moderate to good construct validity for the majority of items of the DOiT questionnaire. Items with poor construct validity (most of them found for items concerning energy intake-related behaviours) should be revised and tested again to improve the questionnaire for future use.
authors.affiliation: 1 Department of Public and Occupational Health, VU University Medical Center, EMGO Institute for Health and Care Research, Van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands.
authors.forename: Evelien H C
authors.initials: EH
authors.lastname: Janssen
authors.affiliation: 1 Department of Public and Occupational Health, VU University Medical Center, EMGO Institute for Health and Care Research, Van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands.
authors.forename: Amika S
authors.initials: AS
authors.lastname: Singh
authors.affiliation: 1 Department of Public and Occupational Health, VU University Medical Center, EMGO Institute for Health and Care Research, Van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands.
authors.forename: Femke
authors.initials: F
authors.lastname: van Nassau
authors.affiliation: 2 Department of Epidemiology and Biostatistics, VU University Medical Center, EMGO Institute for Health and Care Research, Amsterdam, The Netherlands.
authors.forename: Johannes
authors.initials: J
authors.lastname: Brug
authors.affiliation: 1 Department of Public and Occupational Health, VU University Medical Center, EMGO Institute for Health and Care Research, Van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands.
authors.forename: Willem
authors.initials: W
authors.lastname: van Mechelen
authors.affiliation: 1 Department of Public and Occupational Health, VU University Medical Center, EMGO Institute for Health and Care Research, Van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands.
authors.forename: Mai J M
authors.initials: MJ
authors.lastname: Chinapaw
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior; D002648:Child; D016208:Databases, Factual; D002149:Energy Intake; D004734:Energy Metabolism; D005260:Female; D015438:Health Behavior; D006801:Humans; D008019:Life Style; D008297:Male; D009765:Obesity / Q000453:epidemiology* / Q000517:prevention & control*; D015203:Reproducibility of Results; D012574:Schools; D011795:Surveys and Questionnaires