***** To join INSNA, visit http://www.insna.org ***** David Nickerson had a clever field experiment examining contagion of turnout. Essentially, the treatment was to knock on doors of two voter households, give a get out the vote pitch to the individual who answered the door, and to see if the _other_ person was more likely to vote (this was compared to a placebo group of alters who received an unrelated pitch regarding recycling). Nickerson found quite a substantial contagion effect (about 60% the size of the impact of receiving the get out the vote pitch directly). dl Nickerson, David W. 2008. "Is Voting Contagious? Evidence from Two Field Experiments," *American Political Science Review* 102(Feb):49-57.<http://www.nd.edu/~dnickers/papers/nickerson.contagion.pdf> <http://www.nd.edu/~dnickers/papers/nickerson.contagion.pdf> http://www.nd.edu/~dnickers/papers/nickerson.contagion.pdf David Lazer (www.davidlazer.com) Associate Professor of Political Science and Computer Science Northeastern University & Director, Program on Networked Governance Harvard Kennedy School Harvard University The netgov blog: http://www.iq.harvard.edu/blog/netgov/ On Sun, Feb 27, 2011 at 4:23 AM, Thomas Valente <[log in to unmask]> wrote: > ***** To join INSNA, visit http://www.insna.org ***** > > Sinan > > I agree, experiments are great when you can do them and we have 2 published > RCTs that I think demonstrate contagion effects. > > > > Valente, T. W*.*, Hoffman, B. R., Ritt-Olson, A., Lichtman, K., & Johnson, > C. A. (2003). The effects of a social network method for group assignment > strategies on peer led tobacco prevention programs in schools. *American > Journal of Public Health*, *93*, 1837-1843. > > > > Valente, T. W., Ritt-Olson, A., Unger, J., Stacy, A., Okamoto, J. & > Sussman, S., (2007). Peer acceleration: Effects of a network tailored > substance abuse prevention program among high risk adolescents. * > Addiction*, *102*, 1804-1815. > > > > - Tom > > > > *From:* Social Networks Discussion Forum > > [mailto:[log in to unmask]] *On Behalf Of *Sinan Aral > *Sent:* Saturday, February 26, 2011 11:03 PM > > *To:* [log in to unmask] > *Subject:* Re: Measuring contagion in longitudinal behavior data > > > > ***** To join INSNA, visit http://www.insna.org ***** > > Steve, > > We have been working on this problem as well. In my opinion, the cleanest > and most reliable way to estimate social contagion or peer effects in > networks is through a randomized trial (see the first paper below, which is > to our knowledge the largest randomized trial of social contagion conducted > to date). You might find the other follow papers interesting as well as they > pertain directly to estimating contagion effects. In the first two papers > there are literature reviews of various prior approaches. The second paper > listed is my comment on Tom's excellent paper with Christophe and Ragu ("Opinion > leadership and contagion in new product diffusion") which discusses the > theories and methods estimating contagion effects in some detail... it is > also in press at Marketing Science. Hope these help! > > Best > > Sinan > > Aral, S. & Walker, D. (Forthcoming) “Creating Social Contagion through > Viral Product Design: A Randomized Trial of Peer Influence in Networks.” *Management > Science*. (conditionally accepted pending minor revisions). > > http://papers.ssrn.com/sol3/papers.cfm?abstract_id=1564856 > > > Aral, S. (in press). “Identifying Social Influence: A Comment on Opinion > Leadership and Social Contagion in New Product Diffusion.” *Marketing > Science*. > > http://mktsci.journal.informs.org/cgi/reprint/mksc.1100.0596v1 > > > Aral, S., Muchnik, L., & Sundararajan, A. 2009. “Distinguishing Influence > Based Contagion from Homophily Driven Diffusion in Dynamic Networks,” *Proceedings > of the National Academy of Sciences*, Dec. 22, 2009, vol. 106, no.51. > > http://www.pnas.org/content/early/2009/12/09/0908800106.full.pdf > > > > > Sinan Aral > > Assistant Professor, NYU Stern School of Business. > > Research Affiliate, MIT Sloan School of Management. > > Personal Webpage: http://pages.stern.nyu.edu/~saral > > SSRN Page: http://ssrn.com/author=110270 > > WIN Workshop: http://www.winworkshop.net > > Twitter: http://twitter.com/sinanaral > > > On 2/26/2011 4:00 AM, Thomas Valente wrote: > > ***** To join INSNA, visit http://www.insna.org ***** > > Steve > > > > The Strange & Tuma 1993 article in AJS calculated 2 terms, infection: > calculated as the number of ego’s alters that adopted an innovation after > ego in the next time period after ego adopted; and susceptibility calculated > as the adoption of ego after his alter adopts. Myers discussed these as > well in a paper on collective violence. I also introduced a term I called > the critical mass (in my 1995 book) which was adoption weighted by the > outdegree of the egos. These are also discussed in the 2005 chapter models > and methods for diffusion and somewhat in my latest book “Social Networks > and Health.” At the macro level you can also calculate rate of diffusion > using curve fitting techniques as discussed in my 1993 paper, covered very > well by Mahajan & Peterson (1985). (And don’t forget the classic Bass > (1969) model.) Of course the best way to estimate contagion is by using the > autoregressive model which is discussed in my 2005 chapter and 2010 book. > There are debates about the statistical validity of this approach but it > is quite versatile and statistical limitations seem to be getting worked > out. The latest example, to my knowledge, is the Iyengar et al. paper due > out in Marketing Science. > > > > Bass, F. M. (1969). A new product growth model for consumer durables. *Management > Science*, *15*, 215-227.Sage. > > > > Iyengar, R., Van den Bulte, C.* *& Valente, T. W.* *(in press). Opinion leadership and contagion in new product diffusion. *Marketing Science*. > > > > Mahajan, V., & Peterson, R. A. (1985). *Models of innovation diffusion*. > Newbury Park, CA. > > > > Myers, D. J. (2000). The diffusion of collective violence: Infectiousness, > susceptibility, and mass media networks. *American Journal of Sociology*, > *106*, 173-208. > > > > Strang, D., & Tuma, N. B. (1993). Spatial and temporal heterogeneity in > diffusion. *American Journal of Sociology*, *99*, 614-639. > > > > Valente, T. W. (1993). Diffusion of innovations and policy > decision-making. *Journal of Communication*, *43*, 30-41. > > > > Valente, T. W. (1995). *Network models of the diffusion of innovations*. > Cresskill, NJ: Hampton Press. > > > > Valente, T. W. (2005). Models and methods for innovation diffusion. In P. > J. Carrington, J. Scott, & S. Wasserman (Eds.) *Models and methods in > social network analysis*. Cambridge, UK: Cambridge University Press. > > > > Valente, T. W. (2005). Social Networks and Health: Models Methods and > Applications. New York: Oxford University Press. > > > > > > -Tom > > > > Thomas W. Valente, PhD > > Current: École des hautes études en santé publique (Rennes/Paris, France) > > Usual: > > Director, Master of Public Health Program > http://www.usc.edu/medicine/mph/ > > Professor, Department of Preventive Medicine > > Keck School of Medicine > > University of Southern California > > 1000 S. Fremont Ave., #8 > > Building A Room 5133 > > Alhambra CA 91803 > > phone: (626) 457-4139; cell: (626) 429-4123 > > email: [log in to unmask] > > > > *Social Networks and Health: Models, Methods, and Applications*: > > http://www.oup.com/us (promo code: 28569) > > *Evaluating Health Promotion Programs*: www.oup-usa.org/ > > *Network Models of the Diffusion of Innovations*: www.hamptonpress.com > > My personal webpage: http://www-hsc.usc.edu/~tvalente/ > > The Empirical Networks Project: http://ipr1.hsc.usc.edu/networks/ > > You Tube video on Diffusion of Innovations: > http://www.youtube.com/watch?v=ZG9dAIBd4xQ > > > > *From:* Social Networks Discussion Forum [mailto:[log in to unmask]<[log in to unmask]>] > *On Behalf Of *Steve Eichert > *Sent:* Friday, February 25, 2011 8:29 PM > *To:* [log in to unmask] > *Subject:* Measuring contagion in longitudinal behavior data > > > > ***** To join INSNA, visit http://www.insna.org ***** Hello SOCNET, > > > > I'm looking for books, papers, algorithms, and/or ideas on how best to > measure contagion in a network. We have longitudinal behavior data for all > actors in a directed network and want to calculate the degree of contagion > occurring between all connected nodes. We would like to use the calculated > "contagion score" to identify nodes that we can do further analysis on, as > well as to measure the overall level of contagion in the network. The > longitudinal behavior data we have indicates how much of something the nodes > within the network are using over time. We're interested in better > understanding the algorithms folks are using for "adoption contagion" > (someone who has already adopted influences a non adopter to adopt) as well > as "behavior contagion" (a high user influences those connected to them to > use more). > > > > Thoughts? > > > > Thanks, > Steve > > _____________________________________________________________________ > 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. > > _____________________________________________________________________ > 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. > > _____________________________________________________________________ > 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. > _____________________________________________________________________ > 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. > _____________________________________________________________________ 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.