Operations & Supply Chain Management

In modern equity markets, traders have a choice of many exchanges, each operating as an electronic limit order book that can be modeled as a pair of multi-class queues operating under the "time/price" priority rule. The dynamics of the exchanges are coupled via price protection mechanisms. We present mathematical models to study the order routing problem, characterize market equilibria, and derive insights about the queue, delay and adverse selection measures for different exchanges. We present some empirical data that supports our findings.

We propose and study a market microstructure model of a stochastic and dynamic matching problem. Sellers arrive over time supplying capacity to this market that is characterized by a feature set that includes its price. Sellers are also characterized by their delay tolerance and financial considerations. In turn, buyers arrive over time seeking capacity and are endowed with a choice model that allows them to compare and tradeoff options that differ in their features and price.

Flow internalization is a prevalent feature of our markets. Broker dealers that internalize flow, defend the practice on the basis that it offers potential price improvement and lowers take fees. This paper studies a mathematical model of limit order book dynamics with and without flow internalization, and derives insights on the effect of the latter on price dynamics and long-run execution costs that are of interest in optimal trade execution and in policy considerations.

Combinatorial auctions (CAs) are multi-unit auction mechanisms in which bidders can bid on combinations of items or packages. CAs have received considerable attention from academia, and their practical use has increased significantly over recent years especially in procurement projects. Units in procurement projects often exhibit cost synergies, and using a CA can be particularly advantageous to the auctioneer because it enables bidders to express their cost synergies in the bidding process.

When the removal of trade barriers coincides with the elimination of inefficient institutions created to manage them, the gains from trade increase. We investigate the change in productivity associated with the removal of quotas on Chinese textile and clothing exporters as well as the elimination of the export licensing regime which managed quota allocation. When quotas were removed in 2005, Chinese export value and quantity surged and export prices declined.

We develop a theoretical model to investigate the incentives for coordinating the positioning and pricing of horizontally differentiated products in the context of a vertical trading relationship between a retailer and multiple suppliers. We also use the model to analyze various trading relationships, such as category management, and characterize the channel efficiency of each, leading to interesting insights about when such practices may be most effective.

The problem of determining nurse staffing levels in a hospital environment is a complex task due to variable patient census levels and uncertain service capacity caused by nurse absenteeism. In this paper, we combine an empirical investigation of the factors affecting nurse absenteeism rates with an analytical treatment of nurse staffing decisions using a novel variant of the newsvendor model. Using data from the emergency department of a large urban hospital, we find that absenteeism rates are correlated with anticipated future nurse workload levels.