title: Methods of quantifying change in multiple risk factor interventions.
abstract: OBJECTIVE
  Risky behaviors such as smoking, alcohol abuse, physical inactivity, and poor diet are detrimental to health, costly, and often co-occur. Greater efforts are being targeted at changing multiple risk behaviors to more comprehensively address the health needs of individuals and populations. With increased interest in multiple risk factor interventions, the field will need ways to conceptualize the issue of overall behavior change.
  
  
  METHODS
  Analyzing data from over 8000 participants in four multibehavioral interventions, we present five different methods for quantifying and reporting changes in multiple risk behaviors.
  
  
  RESULTS
  The methods are: (a) the traditional approach of reporting changes in individual risk behaviors; (b) creating a combined statistical index of overall behavior change, standardizing scores across behaviors on different metrics; (c) using a behavioral index; (d) calculating an overall impact factor; and (e) using overarching outcome measures such as quality of life, related biometrics, or cost outcomes. We discuss the methods' interpretations, strengths, and limitations.
  
  
  CONCLUSIONS
  Given the lack of consensus in the field on how to examine change in multiple risk behaviors, we recommend researchers employ and compare multiple methods in their publications. A dialogue is needed to work toward developing a consensus for optimal ways of conceptualizing and reporting changes in multibehavioral interventions.
authors.affiliation: Department of Psychiatry, University of California, San Francisco, 401 Parnassus Ave - TRC 0984, San Francisco, CA 94143-0984, USA. JProchaska@ucsf.edu
authors.forename: Judith J
authors.initials: JJ
authors.lastname: Prochaska
authors.forename: Wayne F
authors.initials: WF
authors.lastname: Velicer
authors.forename: Claudio R
authors.initials: CR
authors.lastname: Nigg
authors.forename: James O
authors.initials: JO
authors.lastname: Prochaska
mesh_terms: D001699:Biometry / Q000379:methods; D015438:Health Behavior; D006293:Health Promotion; D006801:Humans; D012107:Research Design; D040242:Risk Reduction Behavior