title: The Multimedia Activity Recall for Children and Adolescents (MARCA): development and evaluation.
abstract: BACKGROUND
  Self-report recall questionnaires are commonly used to measure physical activity, energy expenditure and time use in children and adolescents. However, self-report questionnaires show low to moderate validity, mainly due to inaccuracies in recalling activity in terms of duration and intensity. Aside from recall errors, inaccuracies in estimating energy expenditure from self-report questionnaires are compounded by a lack of data on the energy cost of everyday activities in children and adolescents. This article describes the development of the Multimedia Activity Recall for Children and Adolescents (MARCA), a computer-delivered use-of-time instrument designed to address both the limitations of self-report recall questionnaires in children, and the lack of energy cost data in children.
  
  
  METHODS
  The test-retest reliability of the MARCA was assessed using a sample of 32 children (aged 11.8 +/- 0.7 y) who undertook the MARCA twice within 24-h. Criterion validity was assessed by comparing self-reports with accelerometer counts collected on a sample of 66 children (aged 11.6 +/- 0.8 y). Content and construct validity were assessed by establishing whether data collected using the MARCA on 1429 children (aged 11.9 +/- 0.8 y) exhibited relationships and trends in children's physical activity consistent with established findings from a number of previous research studies.
  
  
  RESULTS
  Test-retest reliability was high with intra-class coefficients ranging from 0.88 to 0.94. The MARCA demonstrated criterion validity comparable to other self-report instruments with Spearman coefficients ranging from rho = 0.36 to 0.45, and provided evidence of good content and construct validity.
  
  
  CONCLUSIONS
  The MARCA is a valid and reliable self-report questionnaire, capable of a wide variety of flexible use-of-time analyses related to both physical activity and sedentary behaviour, and offers advantages over existing pen-and-paper questionnaires.
authors.affiliation: School of Education, Flinders University, Adelaide, Australia. kate.ridley@flinders.edu.au
authors.forename: Kate
authors.initials: K
authors.lastname: Ridley
authors.forename: Tim S
authors.initials: TS
authors.lastname: Olds
authors.forename: Alison
authors.initials: A
authors.lastname: Hill