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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


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:
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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

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]] 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

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_____________________________________________________________________ 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.