title: Classroom-based surveys of adolescent risk-taking behaviors: reducing the bias of absenteeism.
abstract: OBJECTIVE
  This investigation examined the effectiveness of intensive efforts to include frequently absent students in order to reduce bias in classroom-based studies.
  
  
  METHODS
  Grade 10 students in 13 New York City high schools (n = 2049) completed self-administered confidential surveys in 4 different phases: a 1-day classroom capture, a 1-day follow-up, and 2 separate 1-week follow-ups. Financial incentives were offered, along with opportunities for out-of-classroom participation.
  
  
  RESULTS
  Findings showed that frequently absent students engaged in more risk behaviors than those who were rarely absent. Intensive efforts to locate and survey chronically absent students did not, however, significantly alter estimates of risk behavior. Weighting the data for individual absences marginally improved the estimates.
  
  
  CONCLUSIONS
  This study showed that intensive efforts to capture absent students in classroom-based investigations are not warranted by the small improvements produced in regard to risk behavior estimates.
authors.affiliation: Department of Health Studies, New York University School of Education, New York City, 10003, USA. sally.guttmacher@nyu.edu
authors.forename: Sally
authors.initials: S
authors.lastname: Guttmacher
authors.forename: Beth C
authors.initials: BC
authors.lastname: Weitzman
authors.forename: Farzana
authors.initials: F
authors.lastname: Kapadia
authors.forename: Sharon L
authors.initials: SL
authors.lastname: Weinberg
mesh_terms: D000041:Absenteeism; D000293:Adolescent; D000294:Adolescent Behavior; D005260:Female; D006801:Humans; D008297:Male; D009519:New York City; D011159:Population Surveillance / Q000379:methods*; D012309:Risk-Taking; D012574:Schools; D015983:Selection Bias; D013334:Students / Q000523:psychology*