At Columbia Business School, our faculty members are at the forefront of research in their respective fields, offering innovative ideas that directly impact the practice of business today. A quick glance at our publication on faculty research, CBS Insights, will give you a sense of the breadth and immediacy of the insight our professors provide.
As a student at the School, this will greatly enrich your education. In Columbia classrooms, you are at the cutting-edge of industry, studying the practices that others will later adopt and teach. As any business leader will tell you, in a competitive environment, being first puts you at a distinct advantage over your peers. Learn economic development from Ray Fisman, the Lambert Family Professor of Social Enterprise and a rising star in the field, or real estate from Chris Mayer, the Paul Milstein Professor of Real Estate, a renowned expert and frequent commentator on complex housing issues. This way, when you complete your degree, you'll be set up to succeed.
Columbia Business School in conjunction with the Office of the Dean provides its faculty, PhD students, and other research staff with resources and cutting edge tools and technology to help push the boundaries of business research.
Specifically, our goal is to seamlessly help faculty set up and execute their research programs. This includes, but is not limited to:
All these activities help to facilitate and streamline faculty research, and that of the doctoral students working with them.
The article offers the authors' views on expatriate management programs and the benefits from executives interacting with the people and institutions of the host country. The idea that international experience or interaction between foreign managers and local people will help managers become more creative, entrepreneurial, and successful is discussed. The concept of integrative complexity in bi-cultural managers which enhances job performance is mentioned.
The Kidney Case is multi-person exercise that involves the allocation of a single kidney. Students read profiles of eight candidates for the kidney and make a first allocation decision. Each candidate was designed to be high on some allocation principles but low or unknown on others (e.g., best, match, time in cue, age, personal responsibility for disease, future benefits to society, etc.). Then, students are put into groups and assigned to advocate for one of the candidates. Each group will prepare and give a 3-minute presentation on why their candidate should receive the kidney.
Emissions abatement alone cannot address the consequences of global warming for weather disasters. We model how society adapts to manage disaster risks to capital stock. Optimal adaptation — a mix of firm-level efforts and public spending — varies as society learns about the adverse consequences of global warming for disaster arrivals. Taxes on capital are needed alongside those on carbon to achieve the first best.
What are the sources of the returns to education? We study the allocation of higher education graduates from public institutions in Ohio across firms. We present three results. First, we confirm findings in the earlier literature of large pay differences across degrees. Second, we show that up to one quarter of pay premiums for higher degrees are explained by between-firm pay differences. Third, higher education degrees are associated with greater representation at the best-paying firms.
This article focuses on the role of threats in negotiations. Broadly speaking, a threat is a proposition that issues demands and warns of the costs of noncompliance. Even if neither party resorts to them, potential threats shadow most negotiations. Researchers have found that people actually evaluate their counterparts more favorably when they combine promises with threats rather than extend promises alone. Whereas promises encourage exploitation, the threat of punishment motivates cooperation.
This paper considers a single-item, periodic-review inventory model with uncertain demands. In contrast to prior treatments of this problem we assume a finite production capacity per period. Assuming stationary data, a convex one-period cost function and a discrete demand distribution, we show (under a few additional unrestrictive assumptions) that a modified base-stock policy is optimal under the average-cost criterion; in addition, we characterize the optimal base-stock level.
This paper considers a single-item, periodic review inventory model with uncertain demands. We assume a finite production capacity in each period. With stationary data, a convex one-period cost function and a continuous demand distribution, we show (under a few additional unrestrictive assumptions) that a modified basic-stock policy is optimal under the discounted cost criterion, both for finite and infinite planning horizons. In addition we characterize the optimal base-stock levels in several ways.
We consider the problem of scheduling n jobs, each with a specific processing requirement, release time and due date on m uniform parallel machines. It is shown that a feasible schedule can be obtained by determining the maximum flow in a network, thus permitting the use of standard network flow codes. Using a specialized maximum flow procedure, the complexity reduces to O(tn3) operations when t is the number of distinct machine types.
This paper presents an allocation model for a perishable product, distributed from a regional center to a given set of locations with random demands. We consider the combined problem of allocating the available inventory at the center while deciding how these deliveries should be performed. Two types of delivery patterns are analyzed: the first pattern assumes that all demand points receive individual deliveries; the second pattern subsumes the frequently occuring case in which deliveries in multistop routes traveled by a fleet of vehicles. Computational experience is reported.
For a collection of agents with von Neumann-Morgenstern preferences, a price-independent income distribution, and identical probability beliefs, there exists a von Neumann-Morgenstern approximate aggregator. The risk tolerance of the approximate aggregator is equal to the sum of the individual agent risk tolerances at prices which yield constant, "risk-free," contingent consumption. The application of the approximate aggregator to standard asset pricing models in finance is discussed briefly.
Some companies consistently enjoy share prices that exceed book value. Such value creators range from giants like Coca-Cola Co., IBM, and Procter & Gamble to less-known small and medium-sized companies like Pall and Shoney's. Other enterprises trade below book value year after year, in both bear and bull markets. Many managers believe that these differences in price to book ratio do not stem from real differences in competitive performance but rather from the capriciousness of the stock market.
Bernard Frieden and Lynne Sagalyn provide an in-depth analysis of several public-private partnerships that have resulted in several large downtown retail redevelopment projects. These projects were dependent in part on an improvement in underlying factors such as the revitalization of the downtown office market. But, more important, these projects owe their existence to innovative entrepreneurial urban policy. This essay shows how current city policies evolved from the experience gained from redevelopment efforts launched under federal auspices, including Great Society programs.
Confronted with soaring business risks and fierce global competition, managers are discovering that the best hope for staying ahead is by joining forces with other companies. By pooling resources and complementary strengths companies can increase productivity and competitive standing in ways they could not do by themselves.
In the classical maximal flow problem, the objective is to maximize the supply to a single sink in a capacitated network. In this paper we consider general capacitated networks with multiple sinks: the objective is to optimize a general "concave" preference relation on the set of feasible supply vectors. We show that an optimal solution can be obtained by a marginal allocation procedure. An efficient implementation results in an adaptation of the augmenting path algorithm. We also discuss an application of the procedure for an investment company that deals in oil and gas ventures.
In many resource allocation problems, the objective is to allocate discrete resource units to a set of activities so as to maximize a concave objective function subject to upper bounds on the total amounts allotted to certain groups of activities. If the constraints determine a polymatroid and the objective is linear, it is well known that the greedy procedure results in an optimal solution. In this paper we extend this result to objectives that are "weakly concave," a property generalizing separable concavity.
Rational restrictions are derived for the values of American options on futures contracts. For these options, the optimal policy, in general, involves premature exercise. A model is developed for valuing options on futures contracts in a constant interest rate setting. Despite the fact that premature exercise may be optimal, the value of this American feature appears to be small and a European formula due to Black serves as a useful approximation. Finally, a model is developed to value these options in a world with stochastic interest rates.
Special algorithms have been developed to compute an optimal (s,S) policy for an inventory model with discrete demand and under standard assumptions (stationary data, a well-behaved one-period cost function, full backlogging and the average cost criterion). We present here an iterative algorithm for continuous demand distributions which avoids any form of prior discretization. The method can be viewed as a modified form of policy iteration applied to a Markov decision process with continuous state space. For phase-type distributions, the calculations can be done in closed form.
This paper analyzes the empirical behavior of stock-return volatilities prior to and subsequent to the ex-dates of stock splits. The evidence demonstrates rather unambiguously that there is, on the average, an approximately 30% "arbitrary" increase in the return standard deviations following the ex-date. The increase holds for both daily and weekly data, and it is not temporary. No explanatory confounding variables, such as institutional frictions affecting price observations, have been identified.
Let P be a polytope in Rn containing the origin in its interior, and let P* be the algebraic dual polytope of P. Let Q Rn x [0,1] be the (n+1)-dimensional polytope that is the convex hull of P x {1} and P* x {0}.
An extended series of economic studies has failed to find any statistically significant impact on national injury rates due to the OSHA. Two distinct explanations for this apparent failure of OSHA have been put forward in these studies. For the purposes of this study, the first of these explanations will be called the "noncompliance hypothesis" and the second will be labeled the "inefficiency hypothesis." The first of these hypotheses leads immediately to two dilemmas, which can only be resolved by expanding the range of issues considered in an analysis of OSHA.
In this paper, insider trading is viewed as a signal of managements' assessments of firms' future prospects and its information content is compared to that in managements' earnings forecasts. These forecasts are explicit statements of managements' assessments of future prospects. A number of measures of insider trading designed to capture the information aspect of trading are investigated.
The presence of traders with superior information leads to a positive bid-ask spread even when the specialist is risk-neutral and makes zero expected profits. The resulting transaction prices convey information, and the expectation of the average spread squared times volume is bounded by a number that is independent of insider activity. The serial correlation of transaction price differences is a function of the proportion of the spread due to adverse selection. A bid-ask spread implies a divergence between observed returns and realizable returns.
We consider a queueing system with two types of servers and two types of customers. General-use servers can provide service to either customer type while limited-use servers can be used only for one of the two. Though the apparent Markovian state space of this system is five-dimensional, we show that an aggregation results in an exact two-dimensional representation that is also Markovian. Matrix geometric theory is used to obtain approximations for the mean delay times and other measures of interest for each customer type.
Improvements in computational methods have resulted in the faster solution of general equilibrium economic models This paper gives a nontechnical introduction to the octahedral algorithm for the solution of economic models.
This paper presents a macroeconomic model containing optimizing, inventory-holding firms that is consistent with a number of prominent empirical regularities concerning fluctuations in output, exchange rates, relative prices, and money. Prices are sticky, but they are not predetermined. Still, our model is consistent with exchange rate overshooting in the sense of Dornbusch. Typical sticky-price models allow a divergence between current production and current demand, but this divergence is never allowed to feed back into the model.
This paper relates New York City's experience since 1975, a period characterized by local economic and fiscal crisis and a gradual recovery from it, to four prevailing themes in the contemporary literature of cities and public administration.
Many companies refuse to face the reality that their businesses are in trouble or that their strategic positions are wrong. Whether a product line is no longer profitable, foreign competition has slowed growth, or technological changes have left them behind, many otherwise well-managed companies hang on for too long to the status quo. In this inflexible posture, managements time and talent go to waste, assets grow sterile, and technology falls behind.
The paper analyzes the use of information in companies planning strategically versus those which are not. This contrast is used to build the case for developing strategic forecasting capability which focuses on a variety of environments, is proactive and interactive, and creates a need for different kinds of data bases and forecasting techniques.
This paper establishes a simple existence proof for a solution to the optimality equations arising in finite undiscounted Markov Renewal Programs, by applying Brouwer's fixed point theorem to the so-called reduced value-iteration operator. Because of its simplicity, our approach lends itself to new existence results for more general models.
This paper adds to recent evidence on market inefficiency in processing information in earnings reports. It documents that short positions taken in sample stocks which did not report earnings by the date expected during the sample period, 1971–1976, would have been abnormally profitable, before transaction costs. This is because late reports, on average, revealed bad news which was not anticipated in market prices prior to the report date.
We examine a queueing system with multiple primary servers and a fewer number of auxiliary servers. There are two classes of customers—those who require service from a primary server working alone and those who require service from a primary server who is assisted by an auxiliary server. Though the apparent Markovian state space is five-dimensional, we show that an aggregation results in an exact two-dimensional representation which is Markovian. Matrix geometric theory is used to obtain approximations for the mean delay and blocking probability of each customer type.
Many queueing situations such as computer, communications and emergency systems have the feature that customers may require service from several servers at the same time. They may thus be delayed until the required number of servers is avialable and servers may be idle when customers are waiting. We consider general server-completion-time distributions and derive approximation methods for the computation of the steady-state distribution of the number of customers in queue as well as the moments of the waiting-time distribution. Extensive computational results are reported.
We develop two efficient procedures for generating cost allocation vectors in the core of a minimum cost spanning tree (m.c.s.t.) game. The first procedure requires O(n 2) elementary operations to obtain each additional point in the core, wheren is the number of users. The efficiency of the second procedure, which is a natural strengthening of the first procedure, stems from the special structure of minimum excess coalitions in the core of an m.c.s.t. game.
This paper attempts to contribute to two rapidly growing branches in economic theory: asset pricing and “overlapping generations” models. The model is formulated and it is shown that equilibrium prices exist, and some of their properties are discussed. Then the model is applied to an asymmetric information environment to see if randomness in the number of informed agents could confuse the uninformed. Surprisingly, it could not.
This paper presents a successive approximation method for solving systems of nested functional equations which arise, e.g., when considering Markov renewal programs in which policies that are maximal gain or optimal under more selective discount — and average overtaking optimality criteria are to be found. In particular, a successive approximation method is given to find the optimal bias vector and bias-optimal policies. Applications with respect to a number of additional stochastic control models are pointed out.
How many patrol cars staffed with a single police officer are needed to provide equivalent police service to an existing system with n two-officer patrol cars? This question is explored for New York City using a multiple patrol car per call priority queueing model. It is shown that a one-officer patrol program is feasible, yet pitfalls exist which could adversely affect its performance. The paper details the process of data analysis and model building and emphasizes the subjective elements that remain in a highly technical OR study.
We explain the observed negative relati between market value of firms and their fund raising activities. Ours is not a signalling model. The firm's objective is to maximize the present value of its income. Considerations of cash availability (liquidity) and unfolding of uncertainty drive our model. Income from operations is an important source of liquidity. Low earnings are associated with low liquidity. Whether earnings are low or not is known to some extent in advance of the realization itself.
Group planning practices of leading American and Australian manufacturing firms are compared and contrasted. Despite some differences, a broad pattern of similarity emerges across many elements of the planning systems.
One of the primary concerns of urban police departments is the effective use of patrol cars. In large cities, police assigned to patrol cars typically account for more than 50% of total police manpower and their allocation has become particularly crucial in light of recent fiscal cutbacks.