***** To join INSNA, visit http://www.insna.org ***** Thanks. Informative indeed. Michał Bojanowski wrote: > Thanks. It is an interesting article indeed > (in fact it was available trough ArXiv since July 2010, > http://arxiv.org/abs/1007.2876). > > The issue revolved into an interesting debate. Partly covered here > http://www.slate.com/id/2250102/ > I blogged about it too > http://brokeringclosure.wordpress.com/2010/07/28/social-contagion-maybe-not/ > > Make sure you read contributions from both "sides", including > > Fowler, James H. and Nicholas A. Christakis. 2008b. “Estimating peer > effects on health in social networks: A response to Cohen-Cole and > Fletcher and Trogdon, Nonnemaker, and Pais.” Journal of Health Eco- > nomics 27:1400–1405. > > and also a recent related paper by Noel& Nyhan > > "The “Unfriending” Problem The Consequences of Homophily in Friendship > Retention for Causal Estimates of Social Influence" > www-personal.umich.edu/~bnyhan/unfriending.pdf > > > > On Wed, Jun 8, 2011 at 7:57 AM, Ilan Talmud<[log in to unmask]> wrote: > >> ***** To join INSNA, visit http://www.insna.org ***** >> Lyons, Russell (2011) "The Spread of Evidence-Poor Medicine via Flawed >> Social-Network Analysis," Statistics, Politics, and Policy: Vol. 2: Iss. 1, >> Article 2. >> DOI: 10.2202/2151-7509.1024 >> Available at: http://www.bepress.com/spp/vol2/iss1/2Abstract >> >> The chronic widespread misuse of statistics is usually inadvertent, not >> intentional. We find cautionary examples in a series of recent papers by >> Christakis and Fowler that advance statistical arguments for the >> transmission via social networks of various personal characteristics, >> including obesity, smoking cessation, happiness, and loneliness. Those >> papers also assert that such influence extends to three degrees of >> separation in social networks. We shall show that these conclusions do not >> follow from Christakis and Fowler's statistical analyses. In fact, their >> studies even provide some evidence against the existence of such >> transmission. The errors that we expose arose, in part, because the >> assumptions behind the statistical procedures used were insufficiently >> examined, not only by the authors, but also by the reviewers. Our examples >> are instructive because the practitioners are highly reputed, their results >> have received enormous popular attention, and the journals that published >> their studies are among the most respected in the world. An educational >> bonus emerges from the difficulty we report in getting our critique >> published. We discuss the relevance of this episode to understanding >> statistical literacy and the role of scientific review, as well as to >> reforming statistics education >> >> ... summarizing the major problems with C&F’s studies: >> 1. The data are not available to others. >> 2. The unavailable data are sparse for friendships. >> 3. The models used to analyze the sparse data contradict the data and the >> conclusions. >> 4. The method used to estimate the dubious models does not apply. >> 5. The statistical significance tests from the questionable estimates do not >> show >> the proposed differences. >> 6. The wrongly proposed differences do not distinguish among homophily, >> environment, >> and induction. >> 7. Associations at a distance are better explained by homophily than by >> induction. >> >> -- >> Prof. Ilan Talmud, Ph.D. >> Head, Economic Sociology, Department of Sociology and Anthropology, >> University of Haifa >> Phones: 972-4-8240992 (office direct) >> 972-4-8240995 / 8249505 (secretaries) >> (cell) 972-522-220914 Fax: 972-4-8240819 >> >> http://soc.haifa.ac.il/~talmud/ >> >> _____________________________________________________________________ SOCNET >> is a service of INSNA, the professional association for social network >> researchers (http://www.insna.org). To unsubscribe, send an email message to >> [log in to unmask] containing the line UNSUBSCRIBE SOCNET in the body of >> the message. >> > > -- Prof. Ilan Talmud, Ph.D. Head, Economic Sociology, Department of Sociology and Anthropology, University of Haifa Phones: 972-4-8240992 (office direct) 972-4-8240995 / 8249505 (secretaries) (cell) 972-522-220914 Fax: 972-4-8240819 http://soc.haifa.ac.il/~talmud/ _____________________________________________________________________ SOCNET is a service of INSNA, the professional association for social network researchers (http://www.insna.org). To unsubscribe, send an email message to [log in to unmask] containing the line UNSUBSCRIBE SOCNET in the body of the message.