Three-Toed Sloth

This Week Today! at the Complex Systems Colloquium

Attention conservation notice: Of interest only if you (1) happen to be in Ann Arbor today, and (2) care about causal inference in social networks. Also, this post was meant to go live over the weekend, but I messed up the timing, so it's probably too late for you to make plans.

I'll be speaking today at the Center for the Study of Complex Systems at the University of Michigan:

"Homophily, Contagion, Confounding: Pick Any Three"

Abstract: One person's behavior can often be predicted from that of their neighbors in a social network. This is sometimes explained by homophily, the tendency to form social ties with others because we resemble them. It is also sometimes explained by social contagion or social influence, the tendency to act like someone because they are our neighbor. We show that, generically, these two mechanisms are confounded with each other, and with the causal effect of an individual's attributes on their behavior. Distinguishing them requires strong assumptions on the parametrization of the social process or on the adequacy of the covariates used (or both). In particular, simple examples show that asymmetries in regression coefficients cannot identify causal effects, and that imitation (a form of social contagion) can produce substantial correlations between an individual's enduring traits and their choices, even when there is no intrinsic affinity between them. We also suggest some possible constructive responses to these non-identifiability results. (Joint work with Andrew Thomas)

Place and Time: 340 West Hall, noon to 1:30 pm. (I believe we will be starting on "Michigan time".)

I was a post-doc at CSCS when I started this weblog, and they still graciously continue to host it. I prefer to think of coming back to give a talk as more "local boy makes good", and less "not getting anywhere after all these years".

Manual trackback of a sort: AnnArbor.com

Self-Centered; Networks; Enigmas of Chance; Complexity