Social networks and collective action in large populations: An application to the Egyptian Arab Spring

We study a dynamic model of collective action in which agents interact and learn through a co-evolving social network. Our approach highlights the importance of communication in this problem and conceives the social network – which is continuously evolving – as the structure through which agents not only interact but also communicate. We consider two alternative scenarios that differ only on how agents form their expectations: while in the “benchmark” context agents are completely informed, in the alternative one their expectations are formed through a combination of local observation and social learning à la DeGroot. We completely characterize the long-run behavior of the system in both cases and show that only in the latter scenario (arguably the most realistic) there is a significant long-run probability that agents eventually achieve collective action within a meaningful time scale. This, we argue, sheds light on the puzzle of how large populations can coordinate on globally desired outcomes. Finally, we illustrate the empirical potential of the model by showing that it can be efficiently estimated for the so-called Egyptian Arab Spring using large-scale cross-sectional data from Twitter

Gender effects for loss aversion: yes, no, maybe?

Gender effects in risk taking have attracted much attention by economists, and remain debated. Loss aversion—the stylized finding that a given loss carries substantially greater weight than a monetarily equivalent gain—is a fundamental driver of risk aversion. We deploy four definitions of loss aversion commonly used in the literature to investigate gender effects. Even though the definitions only differ in subtle ways, we find women to be more loss averse than men according to one definition, while another definition results in no gender differences, and the remaining two definitions point to women being less loss averse than men. Conceptually, these contradictory effects can be organized by systematic measurement error resulting from model mis-specifications relative to the true underlying decision process

Commitment and cooperation in partnerships.

This thesis uses experimental methods to investigate whether pledges of commitment can improve cooperation in partnerships facing a social dilemma. In the game studied, subjects form partnerships endogenously and choose contribution levels to a partnership account. The treatments vary in terms of the individual’s (a) opportunity to commit to their partner, (b) the cost of dissolving committed partnerships, and (c) the distribution of these dis-solution costs between partners. I find that pledges of commitment can increase cooperation levels within partnerships. Cooperation increases when committed partnerships can be dissolved without cost due to an increase in partnership stability; stable partnerships are more cooperative. I also find pledges of commitment improve cooperation when it is costly to dissolve a committed partnership. Dissolution costs are most effective when they are shared between committed partners because both partners respond to the threat of costly dissolution. Surprisingly, the increase in average cooperation when committed partnerships can be dissolved without cost is of similar magnitude to the increase when dissolution costs are equally shared between committed partners.Thesis (M. Phil.) -- University of Adelaide, School of Economics, 2012

The regulation of public service broadcasters: should there be more advertising on television?

Increased competition for viewers’ time is threatening the viability of public-service broadcasters (PSBs) around the world. Changing regulations regarding advertising minutes might increase revenues, but little is known about the structure of advertising demand. To address this problem, we collect a unique dataset on monthly impacts (quantities) and prices of UK television channels between 2002 and 2009 to estimate the (inverse) demand for advertising on both public and commercial broadcasters. We find that increasing PSB advertising minutes to the level permitted for non-PSBs would increase PSB and industry revenue by 10.5% and 6.7%

Pledges of commitment and cooperation in partnerships

We use experimental methods to investigate whether pledges of commitment can improve cooperation in endogenously formed partnerships facing a social dilemma. Treatments vary in terms of the individual’s (a) opportunity to commit to their partner, (b) the cost of dissolving committed partnerships, and (c) the distribution of these dissolution costs between partners. Our findings show that pledges of commitment alone can increase cooperation and welfare in committed partnerships . The introduction of relatively large and equally split costs yields similar gains. In contrast, when costs to dissolve committed partnerships fall solely on the individual choosing to break up, pledges of commitment fail to improve cooperation and welfare

Online Word of Mouth and the Performance of New Products

We investigate the effects of online word of mouth on the demand for new products using Twitter data. Twitter can both generate buzz & awareness as well as provide information on product quality that can readily diffuse through the population. Leveraging comprehensive data from the US movie industry and Twitter, we estimate a structural model of consumer demand for attending theatrical releases in 2014-2015 that incorporates both information channels. The results show that both channels are important, but differ across types of movies. We find pre-release tweet volume is the most important channel for large franchise movies, generating buzz that influences box office earnings on the opening weekend. Demand for mid tier movies responds to increasing awareness driven by the volume of tweets posted after a movie is released. In contrast, the sentiment expressed in online WoM after a movie’s release influences box office demand in subsequent weekends for smaller movies

Are You Okay? Effects of a National Peer-Support Campaign on Mental Health

National public health awareness campaigns that emphasize peer-to-peer support are being increasingly adopted by governments and NGOs, but evidence on the effect of peer-based support programs at scale is limited. Using quasi-experimental methods, we examine whether a prominent, nationwide peer-based support campaign, “R U OK? Day”, that addresses awareness of mental health and suicide prevention affects short-term mental health outcomes in Australia. Using variation in daily records and differences in the campaign’s intensity over nine years, we find positive effects on mental wellbeing, particularly among middle-aged males, with improved social support the likely mechanism. However, we find no evidence that this effect translates into reduced suicides or suicidal behaviours in the short term. Our results provide evidence that peer support campaigns may be a practical, low-cost approach to improve population mental wellbeing

Riot Networks and the Tullock Paradox: An application to the Egyptian Arab Spring

We study a dynamic model of collective action in which agents interact and learn through a co-evolving social network. We consider two alternative scenarios that differ on how agents form their expectations: while in a "benchmark" agents are assumed completely informed of the prevailing state, in the other context agents shape their expectations through a combination of local observation and social learning a la DeGroot. We completely characterize the long-run behavior of the system in both cases and show that only in the latter scenario (arguably the most realistic) there is a significant long-run probability of successful collective action within a meaningful time scale. This, we argue, sheds light on the puzzle of how large populations can “achieve” collective action. Finally, we illustrate the empirical potential of the model by showing that it can be efficiently estimated for the so-called Egyptian Arab Spring using largescale cross-sectional data from Twitter