title: Recommendations to improve the accuracy of estimates of physical activity derived from self report.
abstract: BACKGROUND
  Assessment of physical activity using self-report has the potential for measurement error that can lead to incorrect inferences about physical activity behaviors and bias study results.
  
  
  OBJECTIVE
  To provide recommendations to improve the accuracy of physical activity derived from self report.
  
  
  METHODS
  We provide an overview of presentations and a compilation of perspectives shared by the authors of this paper and workgroup members.
  
  
  RESULTS
  We identified a conceptual framework for reducing errors using physical activity self-report questionnaires. The framework identifies 6 steps to reduce error: 1) identifying the need to measure physical activity, 2) selecting an instrument, 3) collecting data, 4) analyzing data, 5) developing a summary score, and 6) interpreting data. Underlying the first 4 steps are behavioral parameters of type, intensity, frequency, and duration of physical activities performed, activity domains, and the location where activities are performed. We identified ways to reduce measurement error at each step and made recommendations for practitioners, researchers, and organizational units to reduce error in questionnaire assessment of physical activity.
  
  
  CONCLUSIONS
  Self-report measures of physical activity have a prominent role in research and practice settings. Measurement error may be reduced by applying the framework discussed in this paper.
authors.affiliation: Program in Exercise and Wellness, School of Nutrition and Health Promotion, Arizona State University, Phoenix, AZ, USA.
authors.forename: Barbara E
authors.initials: BE
authors.lastname: Ainsworth
authors.forename: Carl J
authors.initials: CJ
authors.lastname: Caspersen
authors.forename: Charles E
authors.initials: CE
authors.lastname: Matthews
authors.forename: Louise C
authors.initials: LC
authors.lastname: Mâsse
authors.forename: Tom
authors.initials: T
authors.lastname: Baranowski
authors.forename: Weimo
authors.initials: W
authors.lastname: Zhu
mesh_terms: D003210:Concept Formation; D003625:Data Collection / Q000379:methods; D004493:Education; D004734:Energy Metabolism; D006801:Humans; D011939:Mental Recall; D009043:Motor Activity / Q000502:physiology*; D015983:Selection Bias; D057566:Self Report