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Dear all,

I wonder if you could please shed light on how to conduct a project
involving social network experiment. Basically, suppose I can conduct the
experiment in roughly 60 middle schools and the outcome I am interested in
is the prevalence of cigarette smoking among students. What experimental
design with social network component will you view or suggest as innovative
and important?

I can think of this on two lines. One is to test an important proposition in
social network analysis that opinion leaders can accelerate the diffusion of
(positive) attitudinal and behavioral changes. There will be three
experimental conditions. The control condition is with no intervention. The
first treatment condition is randomly picking changing agents. The second
treatment condition is picking the opinion leaders as change agents. Then we
compare the efficacy of these three conditions. Of course, we can add some
twist to the procedure of how to pick opinion leaders, like contrasting
opinion leaders chosen using in-degree with those chosen with eigenvector
centrality or others, etc. I know there were a lot of studies using
variations of this kind of design (Kelly et al. 1991; Latkin 1998; Valente
and Davis 1999; Sikkema et al. 2000; Larkey et al. 2002; Stoty et al. 2002;
Woff et al. 2004; Valente 2005), but I did not see any studies directly and
purely using this design in public health literature. Does this design seem
too obvious? I am also concerned that the individual-based interventions of
this design may not be effective at all.

The other is to use group intervention. For example, Wing and Jeffery (1999)
showed that group treatment was more effective than individual treatment in
a weight loss program.

Some studies like Buller et al. (2000) and Valente (2003) combined the above
two approaches, using opinion leaders to lead group interventions. I am
concerned with interference between groups or cliques as called in Buller et
al. (2000).  Also, the combination makes it hard to disentangle which
network feature, between opinion leaders and group cohesion, matters in
terms of preventing cigarette smoking.

I am also concerned with the unit of analysis. Because the number of schools
are small (some may even drop off when they are asked to sign up), I thought
about conducting the randomization on classroom level. But the interference
between classrooms may become a big problem for inference of the
intervention effects.

Whether you happen to work on this area or not, I would really appreciate
your comments on my concerns and suggestions on how to make an "innovative"
social network experiment given the above constrains, etc. Any perspective
will be extremely welcomed. Thanks very much!



Weihua (Edward) An

Ph.D. Candidate in Sociology
Doctoral Fellow in Social Policy
Graduate Associate of IQSS
Harvard University
568 William James Hall
33 Kirkland Street
Cambridge, MA  02138

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