title: Does social desirability compromise self-reports of physical activity in web-based research?
abstract: BACKGROUND
  This study investigated the relation between social desirability and self-reported physical activity in web-based research.
  
  
  RESULTS
  A longitudinal study (N = 5,495, 54% women) was conducted on a representative sample of the Dutch population using the Marlowe-Crowne Scale as social desirability measure and the short form of the International Physical Activity Questionnaire. Social desirability was not associated with self-reported physical activity (in MET-minutes/week), nor with its sub-behaviors (i.e., walking, moderate-intensity activity, vigorous-intensity activity, and sedentary behavior). Socio-demographics (i.e., age, sex, income, and education) did not moderate the effect of social desirability on self-reported physical activity and its sub-behaviors.
  
  
  CONCLUSIONS
  This study does not throw doubt on the usefulness of the Internet as a medium to collect self-reports on physical activity.
authors.affiliation: CAPHRI, Maastricht University, The Netherlands. rik.crutzen@maastrichtuniversity.nl
authors.forename: Rik
authors.initials: R
authors.lastname: Crutzen
authors.forename: Anja S
authors.initials: AS
authors.lastname: Göritz
mesh_terms: D000328:Adult; D000368:Aged; D015982:Bias; D015444:Exercise / Q000523:psychology; D005260:Female; D015438:Health Behavior; D006293:Health Promotion / Q000379:methods; D006801:Humans; D020407:Internet; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D009426:Netherlands; D012107:Research Design; D057185:Sedentary Behavior; D057566:Self Report; D012928:Social Desirability; D016138:Walking / Q000523:psychology