How many X's do you know'' surveys - Columbia University

Overview
Social and political polarization
Background: how many people do you know?
Learning from “How many X’s do you know” surveys
Next
The overdispersed model
3 models
Fitting our model
Results: how many people do you know?
Results: group sizes and overdispersions
Confidence building and model extensions
◮ data model: y ik ∼ Negative-binomial(e α i +β k
, ω k ), for
i = 1, . . . , 1370, k = 1, . . . , 32
◮ prior dists
◮ α i ∼ N(µ α , σα), 2 for i = 1, . . . , 1370
◮ β k ∼ N(µ β , σβ 2 ), for k = 1, . . . , 32
◮ ω k ∼ U(1, 20), for k = 1, . . . , 32
◮ hyperprior dist: p(µ α , µ β , σ α , σ β ) ∝ 1
◮ 1370 + 32 + 32 + 4 parameters to estimate
◮ Nonidentifiability in α + β (to be discussed soon)
Gelman, DiPrete, Salganik, Teitler, Zheng
Studying polarization using surveys