Testing for Peer Effects without Specifying the Network Structure

Author:

Hyunseok Jung, Xiaodong Liu

Keyword:

Economics, Econometrics, Econometrics (econ.EM)

journal:

date:

2023-06-15 16:00:00

Abstract

This paper proposes an Anderson-Rubin (AR) test for the presence of peer effects in panel data without the need to specify the network structure. The unrestricted model of our test is a linear panel data model of social interactions with dyad-specific peer effects. The proposed AR test evaluates if the peer effect coefficients are all zero. As the number of peer effect coefficients increases with the sample size, so does the number of instrumental variables (IVs) employed to estimate the unrestricted model, rendering Bekker's many-IV environment. By extending existing many-IV asymptotic results to panel data, we show that the proposed AR test is asymptotically valid under the presence of both individual and time fixed effects. We conduct Monte Carlo simulations to investigate the finite sample performance of the AR test and provide two applications to demonstrate its empirical relevance.

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