SUPPLEMENT TO “LIBERATION TECHNOLOGY: MOBILE PHONES AND POLITICAL MOBILIZATION IN AFRICA” (Econometrica, Vol. 88, No. 2, March 2020, 533–567)

A.1.1. Setup WE CONSIDER a network of individuals characterized by the distribution P(d) (d = 0 1 D) of the number d of neighbors or degree, where ∑D d=0 P(d) = 1. We regard mobile phones as increasing the number of neighbors and, as a result, increasing the density of the network. We revert to a more formal definition of network density below. Each agent i has the choice between taking action 0, the status quo (in the present case, not protesting), or action 1 (in the present case, protesting). We denote the utility of an agent of degree di from taking action 1 relative to action 0 when he expects his neighbors to choose action 1 with probability ȳ−i by vi = v(di ȳ−i). We follow others in the literature (e.g., Granovetter (1978), Jackson and Yariv (2007)) and assume that agents’ decisions are characterized by strategic complementarities, that is, that the utility of agent i from taking action 1 is nondecreasing in ȳ−i: