Decision Making & Negotiations

Identity movements rely on a shared "we-feeling" amongst a community of participants. In turn, such shared identities are possible when movement participants can self-categorize themselves as belonging to one group. We address a debate as to whether community diversity enhances or impedes such protests, and investigate the role of racial diversity since it is a simple, accessible, and visible basis of community diversity and social categorization.

Financial crises appear to be a common and fairly constant feature of the economic cycle. Banking crises, a distinct subset of financial crises, consist either of panics, moments of temporary confusion about the unobservable incidence across the financial system of observable aggregate shocks, or severe waves of bank failures which result in aggregate negative net worth of failed banks in excess of one percent of GDP.

Lawrence Glaubinger, a Columbia Business School alumnus, became increasingly involved in running his 100-acre Christmas tree farm after he retired in 1992. Between 1993 and 2008, Glaubinger sold Ponderosa pines through an arrangement with Green Acres, a large retailer that bought Glaubinger's trees to sell at its nurseries. While Glaubinger Tree Farm sold the trees to Green Acre at a wholesale price based on its marginal cost, the retailer independently set retail pricing. Glaubinger suspected his tree farm could have shown higher profits if it had sold directly to consumers.

Hospital ambulance diversions are prevalent and increasing nationwide as emergency departments experience growing congestion. Using negative binomial regressions, this paper links the number of acute myocardial infarction (AMI) deaths to the level and extent of diversion in the five boroughs of New York City. The results indicate that both high levels of ambulance diversion and simultaneous diversion across hospitals are associated with increasing numbers of deaths from AMI.

The banking legislation of the 1930s took very little time to pass, was unusually comprehensive, and unusually responsive to public opinion. Ironically, the primary motivations for the main bank regulatory reforms in the 1930s (Regulation Q, the separation of investment banking from commercial banking, and the creation of federal deposit insurance) were to preserve and enhance two of the most disastrous policies that contributed to the severity and depth of the Great Depression — unit banking and the real bills doctrine.

Particle learning (PL) provides state filtering, sequential parameter learning and smoothing in a general class of state space models. Our approach extends existing particle methods by incorporating the estimation of static parameters via a fully-adapted filter that utilizes conditional sufficient statistics for parameters and/or states as particles. State smoothing in the presence of parameter uncertainty is also solved as a by-product of PL. In a number of examples, we show that PL outperforms existing particle filtering alternatives and proves to be a competitor to MCMC.