  Many economic activities are embedded in networks: sets of agents and the
(often) rivalrous relationships connecting them to one another. Input sourcing
by firms, interbank lending, scientific research, and job search are four
examples, among many, of networked economic activities. Motivated by the
premise that networks' structures are consequential, this chapter describes
econometric methods for analyzing them. I emphasize (i) dyadic regression
analysis incorporating unobserved agent-specific heterogeneity and supporting
causal inference, (ii) techniques for estimating, and conducting inference on,
summary network parameters (e.g., the degree distribution or transitivity
index); and (iii) empirical models of strategic network formation admitting
interdependencies in preferences. Current research challenges and open
questions are also discussed.
