"Fishing, Commitment, and Communication" (Preprint)
(Forthcoming, Political Analysis) (with P van der Windt and R Sanchez de la Sierra). Even though everyone knows it is wrong, it is common practice in empirical social science to select what results to report only after
analysing data. This practice of "data fishing" can result in enormous bias and an unreliable body of published research. We argue here that it is time to put a stop to this practice
by introducing norms for research registration in political science. We describe the scope for bias under weak registration systems and discuss likely effects of registration on the sort of research that gets produced and reported.
Impacts of Development Aid (Again)
"Democratic Institutions and Collective Action Capacity"
(with J Fearon and J Weinstein) (Working paper). Results from a field experiment with behavioral measures in Liberia to try to work out the effects of community driven development interventions on cooperation.
We find overall positive effects but strong heterogeneity suggesting that the effect of these interventions depends strongly on the nature of collective action problems facing communities.
"Can compactness constrain the gerrymander?"
(preprint) (gated copy). Irish Political Studies. also in Hard Questions for Democracy (2012))
(2012) Gerrymandering produces oddly shaped constituencies that result in electoral outcomes that are unrepresentative of population preferences. This note shows that no shape constraints can prevent gerrymandering and indeed odd shapes may be required to ensure minimal representativeness; this clarifies that the problem of representativeness follows from
two party first past the post system, not from the shape of constituencies.
"Spatial Models, Cognitive Metrics and Majority Rule Equilibria"
(with M Laver) British Journal of Political Science. [Replication files (R) for Table 1 and Figure 3]
A tragedy of majority rule is that in general when you have complex policy choices to make you will find that for any proposed outcome there will always be some majority that would prefer something else.
We show that there might be a solution to this problem if people calculate political distances by simply adding up differences across multiple dimensions of policy.
Coethnicity: Diversity and the Dilemmas of Collective Action
(with J Habyarimana, D Posner and J Weinstein)   New York: Russell Sage Press
| Chapter 1
| Buy at Amazon In this book we try to work out why diverse groups often have problems working together. We analyze data from a suite of experiments that we ran in Kampala, Uganda,
and find that in that context at least the problem doesn't seem to lie in fundamental incompatibilities but rather with the strategies that have been adopted to regulate within group behavior.
"Field Experiments and the Political Economy of Development"
(with J Weinstein) Annual Review of Political Science There is a lot of potential for researchers and development organizations to work together to use experimental approaches in order to learn about basic development processes. We describe the opportunities and limitations of this approach.
2008 "Who Fights?"
(with J Weinstein). American Journal of Political Science. Data We use data from our survey of rebels and self defense militia to try to work out why some people take part in violent movements.
We find that poverty is a strong driver, but inconsistent with the classic grievance hypothesis, we find that poverty is associated with people joining both sides of the war.
Decision-making between fragmented groups:
2008 "Existence of a Multicameral Core"
Social Choice and Welfare   | Additional Material In formal models of majority rule we know that if a single group makes a decision an equilibrium typically exists at the "median" in one dimension but there is no clear prediction in more than one dimension. Here I show
that if n groups jointly make a decision in m dimensions, outcomes lie on a "median hyperplane" if m &le n but difficulties reemerge in higher dimensions.
Game theoretic analysis of coalitions:
Annual Review of Political Science I review the formal literature on coalitions and coalition formation. In recent years there has been excellent work linking cooperative to noncooperative approaches.
The next frontier in this work is examining how variation in the rules governing how and which contracts are signed affects what sorts of coalitions are likely to form.
2007 "Demobilization and Reintegration"
(with J Weinstein) Journal of Conflict ResolutionData Lots of resources are put into assisting excombatants return to civilian life. But we don't understand the reintegration process well and whether interventions to support it are effective.
We find that a history of abuse is a good predictor of reintegration difficulties but we find no evidence of the effectiveness of UN programs (although we emphasize that no evidence of an effect is not the same as evidence of no effect!).
2007 "Strategic Ratification"   Public Choice I examine the conjecture that bargainers are much more effective when their deals are subject to ratification by third parties with different preferences to their own. By examining a general setting in which
ratifiers are fully strategic I find conditions under which this conjecture holds.
2007 "The Political Economy of Natural Resource Funds," (with M Sandbu) in
Humphreys, Sachs, and Stiglitz (eds.) Escaping the Resource Curse
| Formal Model | Data In this chapter we propose a political economy model to help understand the incentives to consume natural resource wealth too quickly. A core problem we identify is that political instability reduce the incentives for politicians to spend optimally.
We describe a set of design elements that could help address the credibility issues that underlie this problem.
The Treatment of Civilians in Civil War:
2006 "Handling and Manhandling Civilians in Civil War" (with J Weinstein)
American Political Science Review | Formal Model We seek to understand why some fighting factions are so much more abusive to civilian populations than others. There are many possible reasons for this; in the Sierra Leone case
variation in the discipline of subfactional units appears best able to account for behavior with civilians. Within both the rebel and the militia groups abuses were significantly more limited in the more disciplined units.
Conflict Onset and Duration:
2005 "Natural Resources, Conflict, and Conflict Resolution"
Journal of Conflict Resolution
| ( JCR link )
| Data I examine what mechanisms might underpin the relationship between natural resource endowments and conflict. There are many possible culprits but overall
explanations that focus on the adverse effects of resources on state structures seem more accurate than explanations that focus on rebel greed.
2005 "Senegal and Mali: A Comparative Study of Rebellions in West Africa" (with H Ag Mohamed) in Collier and Sambanis Understanding Civil War Africa: Africa Evidence And Analysis We examine the origin and duration of two secessionist wars in West Africa. Resource endowments do not help account for the origins of the wars although they may help explain the duration of the Senegal conflict. More important factors appear to be patterns of within country inequality as well as regional neighborhood effects.
Democracy and Growth:
Political Institutions and Economic Policies: Lessons from Africa" (with Robert Bates.) British Journal of Political Science (2005) 35:403-428
We examine the effects of democratic institutions on policy choices; more competitive systems we find are associated with less corruption but not with a greater propensity to adopt "Washington Consensus" policies.