We conduct a large scale RCT to investigate peer effects in computer assisted learning (CAL). Identification of peer effects relies on three levels of randomization. It is already known that CAL improves math test scores in Chinese rural schools. We find that paired treatment improves the...

Using a large administrate dataset covering the universe of phone calls and airtime transfers in a country over a four year period, we examine the pattern of adoption of airtime transfers over time. We start by documenting strong network effects: increased usage of the new airtime transfer...