Review A primer on the use of cluster analysis or factor analysis to assess co-occurrence of risk behaviors Hedwig Hofstetter ⁎, Elise Dusseldorp, Pepijn van Empelen, Theo W.G.M. Paulussen TNO (Netherlands Organization for Applied Scientific Research), Expertise Group Life Style, The Netherlands abstract article info Available online 15 July 2014 Keywords: Health behaviors Multiple risk behavior Clusters Factors Objective: The aim of this paper is to provide a guideline to a universal understanding of the analysis of co-occurrence of risk behaviors. The use of cluster analysis and factor analysis was clarified. Method: A theoretical introduction to cluster analysis and factor analysis and examples from literature were provided. A representative sample (N = 4395) of the Dutch population, aged 16–40 and participating from fall 2005 to spring 2006, was used to illustrate the use of both techniques in assessing the co-occurrence of risk behaviors. Results: Whereas cluster analysis techniques serve to focus on particular clusters of individuals showing the same behavioral pattern, factor analysis techniques are used to assess possible groups of interrelated health-risk behaviors that can be explained by an unknown common source. Choice between the techniques partly depends on the research question and the aim of the research, and has different implications for inferences and policy. Conclusion: By integrating theory and results from an illustrative example, a guideline has been provided that contributes towards a systematic approach in the assessment of co-occurrence of risk behaviors. Following this guideline, a better comparison between outcomes from various studies is expected, leading to improved effec- tiveness of multiple behavior change interventions. © 2014 Elsevier Inc. All rights reserved. Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141 Cluster analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142 Theory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142 Examples from literature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143 Factor analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143 Theory. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143 Examples from literature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144 Illustrative example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144 A first setup to a guideline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145 Conflict of interest statement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146 Introduction Over the past decades, there has been growing interest in research on associations of lifestyle-risk behaviors (see, for example, Bailey et al., 2006; de Vries et al., 2008; Prochaska, 2008; Pronk et al., 2004). Many studies have focused on four major lifestyle-risk factors, namely physical inactivity, smoking, drinking and nutrition or diet (e.g., Bailey et al., 2006; Conry et al., 2011; de Vries et al., 2008; Heroux et al., 2012; Laska et al., 2009; Lippke et al., 2012; Poortinga, 2007; Schuit et al., 2002; Van Nieuwenhuizen et al., 2009). Other factors have also been examined, such as psychological stress (Dodd et al., 2010), delin- quency behavior (Van Nieuwenhuizen et al., 2009), drug use (Faeh Preventive Medicine 67 (2014) 141–146 ⁎ Corresponding author at: TNO, Expertise Group Life Style, P.O. Box 3005, 2301 DA Leiden, The Netherlands. E-mail address: hedwig.hofstetter@tno.nl (H. Hofstetter). http://dx.doi.org/10.1016/j.ypmed.2014.07.007 0091-7435/© 2014 Elsevier Inc. All rights reserved. Contents lists available at ScienceDirect Preventive Medicine journal homepage: www.elsevier.com/locate/ypmed