title: Validation of a previous-day recall measure of active and sedentary behaviors.
abstract: OBJECTIVE
  A previous-day recall (PDR) may be a less error-prone alternative to traditional questionnaire-based estimates of physical activity and sedentary behavior (e.g., past year), but the validity of the method is not established. We evaluated the validity of an interviewer administered PDR in adolescents (12-17 yr) and adults (18-71 yr).
  
  
  METHODS
  In a 7-d study, participants completed three PDR, wore two activity monitors, and completed measures of social desirability and body mass index. PDR measures of active and sedentary time was contrasted against an accelerometer (ActiGraph) by comparing both to a valid reference measure (activPAL) using measurement error modeling and traditional validation approaches.
  
  
  RESULTS
  Age- and sex-specific mixed models comparing PDR to activPAL indicated the following: 1) there was a strong linear relationship between measures for sedentary (regression slope, β1 = 0.80-1.13) and active time (β1 = 0.64-1.09), 2) person-specific bias was lower than random error, and 3) correlations were high (sedentary: r = 0.60-0.81; active: r = 0.52-0.80). Reporting errors were not associated with body mass index or social desirability. Models comparing ActiGraph to activPAL indicated the following: 1) there was a weaker linear relationship between measures for sedentary (β1 = 0.63-0.73) and active time (β1 = 0.61-0.72), (2) person-specific bias was slightly larger than random error, and (3) correlations were high (sedentary: r = 0.68-0.77; active: r = 0.57-0.79).
  
  
  CONCLUSIONS
  Correlations between the PDR and the activPAL were high, systematic reporting errors were low, and the validity of the PDR was comparable with the ActiGraph. PDR may have value in studies of physical activity and health, particularly those interested in measuring the specific type, location, and purpose of activity-related behaviors.
authors.affiliation: Nutritional Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD 20892-9704, USA. charles.matthews2@nih.gov
authors.forename: Charles E
authors.initials: CE
authors.lastname: Matthews
authors.forename: Sarah Kozey
authors.initials: SK
authors.lastname: Keadle
authors.forename: Joshua
authors.initials: J
authors.lastname: Sampson
authors.forename: Kate
authors.initials: K
authors.lastname: Lyden
authors.forename: Heather R
authors.initials: HR
authors.lastname: Bowles
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Moore
authors.forename: Amanda
authors.initials: A
authors.lastname: Libertine
authors.forename: Patty S
authors.initials: PS
authors.lastname: Freedson
authors.forename: Jay H
authors.initials: JH
authors.lastname: Fowke
mesh_terms: D056044:Actigraphy; D000203:Activities of Daily Living; D000293:Adolescent; D000328:Adult; D000368:Aged; D015992:Body Mass Index; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D011939:Mental Recall; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D057185:Sedentary Behavior; D012928:Social Desirability; D055815:Young Adult