title: Including questionnaires with the invitation package appeared to increase the response fraction among women.
abstract: OBJECTIVE
  The Breast Cancer Environment and Employment Study (BCEES) is a case--control study that began in 2009. The study experienced a lower than expected response fraction, a trend that appears to be occurring internationally. A 32-page questionnaire was included in the initial invitation to participate, and previous research suggests that long questionnaires decrease response fractions. The aim of this study was to test whether removal of the questionnaire from the invitation package increased participation.
  
  
  METHODS
  A randomized controlled trial was undertaken among the BCEES controls from June to August 2010. One group of 250 received the questionnaire in the initial invitation package, and the other group of 250 received only the invitation package and was sent the questionnaire after their consent was received. The proportion of responses for the two groups was compared using contingency tables and chi-square statistics.
  
  
  RESULTS
  Those who received the questionnaire with the invitation package were more likely to consent to participate than those who did not (40.8% and 33.2%, respectively). However, this difference was not statistically significant (P=0.078).
  
  
  CONCLUSIONS
  To improve response fractions and reduce time in following up nonresponses, questionnaires should be included in the invitation package.
authors.affiliation: Western Australian Institute for Medical Research, The University of Western Australia, B Block, Hospital Avenue, Nedlands, WA 6009, Australia.
authors.forename: Pierra A
authors.initials: PA
authors.lastname: Rogers
authors.forename: Livia
authors.initials: L
authors.lastname: Haddow
authors.forename: Allyson K
authors.initials: AK
authors.lastname: Thomson
authors.forename: Lin
authors.initials: L
authors.lastname: Fritschi
authors.forename: Jen
authors.initials: J
authors.lastname: Girschik
authors.forename: Terry
authors.initials: T
authors.lastname: Boyle
authors.forename: Sonia
authors.initials: S
authors.lastname: El Zaemey
authors.forename: Jane S
authors.initials: JS
authors.lastname: Heyworth
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000628:therapy; D016022:Case-Control Studies; D015709:Correspondence as Topic; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D010358:Patient Participation; D011795:Surveys and Questionnaires