Columbia Business School Research

According to human capital theory, technological change will influence the retirement decisions of older workers in two ways. First, workers in industries with high rates of technological change will retire later if there is a net positive correlation between technological change and on-the-job training. Second, an unexpected change in the rate of technological change will induce older workers to retire sooner because the required amount of retraining will be an unattractive investment.

We develop a simple O(n log n) solution method for the standard lot-sizing model with backlogging and a study horizon of n periods. Production costs are fixed plus linear and holding and backlogging costs are linear with general time-dependent parameters. The algorithm has linear [O(n)] time complexity for several important subclasses of the general model. We show how a slight adaptation of the algorithm can be used for the detection of a minimal forecast horizon and associated planning horizon.

We consider distribution systems with a single depot and many retailers each of which faces external demands for a single item that occurs at a specific deterministic demand rate. All stock enters the systems through the depot where it can be stored and then picked up and distributed to the retailers by a fleet of vehicles, combining deliveries into efficient routes. We extend earlier methods for obtaining low complexity lower bounds and heuristics for systems without central stock.

We investigate the stability of waiting-time derivatives when inputs to a queueing system-service times and interarrival times-depend on a parameter. We give conditions under which the sequence of waiting-time derivatives admits a stationary distribution, and under which the derivatives converge to the stationary regime from all initial conditions. Further hypotheses ensure that the expectation of a stationary waiting-time derivative is, in fact, the derivative of the expected stationary waiting time.

We consider a production/distribution network represented by a general directed acyclic network. Each node is associated with a specific "product" or item at a given location and/or production stage. An arc (i, j) indicates that item i is used to "produce" item j. External demands may occur at any of the network's nodes. These demands occur continuously at item specific constant rates. Components may be assembled in any given proportions.

This paper assesses policies of mass privatization in Germany, Czechoslovakia, Hungary and Poland. A central concern stemming from the analysis is that, in view of the fiscal crisis facing economies in transition, it is crucial for governments to try to maximize the proceeds from the sale of state assets. Because of the low initial level of private wealth, it is important, in this respect, to let potential buyers borrow from the government or issue claims on future revenues (obtained with the privatized assets) to the government in order to pay for the privatized firms.

We analyze incomplete long-term financial contracts between an entrepreneur with no initial wealth and a wealthy investor. Both agents have potentially conflicting objectives since the entrepreneur cares about both pecuniary and non-pecuniary returns from the project while the investor is only concerned about monetary returns.

Research was conducted to investigate the value implications of the changes in annual earnings. It was assumed that a relationship exists between the persistence of earnings and the changes in stock prices associated with reported earnings innovations. The study yielded three major findings. Results showed that other data contained in annual financial statements can be used to evaluate pricing multipliers. Findings also revealed the variability of the persistence of earnings and the pricing multipliers indicated by financial statements.

This note shows that in environments without externalities or aggregate feasibility constraints, extremely simple mechanisms can be used to approximately ("virtually") implement social choice functions in iteratively strictly undominated strategies.

The paper first characterizes the predictable components in excess rates of returns on major equity and foreign exchange markets using lagged excess returns, dividend yields, and forward premiums as instruments. Vector autoregressions (VARs) demonstrate one-step-ahead predictability and facilitate calculations of implied long-horizon statistics, such as variance ratios. Estimation of latent variable models then subjects the VARs to constraints derived from dynamic asset pricing theories.

We derive conditions under which the increments of a vector process are associated—i.e., under which all pairs of increasing functions of the increments are positively correlated. The process itself is associated if it is generated by a family of associated and monotone kernels. We show that the increments are associated if the kernels are associated and, in a suitable sense, convex. In the Markov case, we note a connection between associated increments and temporal stochastic convexity.

Common random numbers (CRN) is a widely-used technique for reducing variance in comparing stochastic systems through simulation. Its popularity derives from its intuitive appeal and ease of implementation. However, though CRN has been observed to work well with a broad range of models, the class of systems for which it is provably advantageous has remained rather limited.

A generalized semi-Markov scheme models the structure of a discrete event system, such as a network of queues. By studying combinatorial and geometric representations of schemes we find conditions for second-order properties—convexity/concavity, sub/supermodularity—of their event epochs and event counting processes. A scheme generates a language of easible strings of events. We show that monotonicity of the event epochs is equivalent to this language forming an antimatroid with repetition.

We establish stochastic monotonicity of the event epoch sequences of generalized semi-Markov processes through the structure of the generalized semi-Markov schemes on which they are based. Our main condition states, roughly, that the occurrence of more events in the short run never leads to the activation of less events in the long run.

Four groups are identified among 113 Fortune 500 manufacturers that approach innovation quite differently. The groups are based on 27 measured elements of formal and informal organization, corporate strategy, and corporate environment. Both financial performance and product innovation differ significantly among the groups. A group of 42 firms that invest heavily in innovation perform the best financially, with a smaller group of firms that are not innovative but which follow a strategy of acquisition performing nearly as well financially.

This paper offers a new theory of limit pricing. Incumbents from different markets or regions "compete" against one another, with each attempting to price in a manner that deflects entry into the others' markets. An entrant is imperfectly informed as to the incumbents' respective investments in cost reduction and seeks to enter markets in which incumbents have high costs. In a focal equilibrium, the entrant uses a simple "comparison strategy," in which it enters only the highest-priced markets, and incumbents engage in limit-pricing behavior.

The paper analyzes the contemporaneous association between market returns and earnings for long return intervals. The research design exploits two fundamental accounting attributes: (i) earnings aggregate over periods, and (ii) expanding the interval over which earnings are determined, is likely to reduce "measurement errors" in (aggregate) earnings. These concepts lead to the level of (aggregate) earnings as a natural earnings variable for explaining security returns.

The reorder point/reorder quantity policies, also referred to as (r, Q) policies, are widely used in industry and extensively studied in the literature. However, for a period of almost 30 years there has been no efficient algorithm for computing optimal control parameteres for such policies. In this paper, we present a surprisingly simple and efficient algorithm for the determination of an optimal (r*, Q*) policy. The computational complexity of the algorithm is linear in Q*.

Countable-state, continuous-time Markov chains are often analyzed through simulation when simple analytical expressions are unavailable. Simulation is typically used to estimate costs or performance measures associated with the chain and also characteristics like state probabilities and mean passage times. Here we consider the problem of estimating derivatives of these types of quantities with respect to a parameter of the process. In particular, we consider the case where some or all transition rates depend on a parameter.

This article explores the differential measurement problems related to the earnings components by invoking the standard errors-in-variables perspective on estimated coefficients. A more traditional way of looking at accounting recognizes the process as one of measurements. That is, the analysis of transactions leads to line items in the financial statements, which in turn aggregate into the bottom line numbers: earnings and book value. The disclosures of the line items clearly suggest that the accountant is aware of the insufficiency of earnings and book values as determinants of values.

Alternative ways of conducting inference and measurement for long-horizon forecasting are explored with an application to dividend yields as predictors of stock returns. Monte Carlo analysis indicates that the Hansen and Hodrick (1980) procedure is biased at long horizons, but the alternatives perform better. These include an estimator derived under the null hypothesis as in Richardson and Smith (1991), a reformulation of the regression as in Jegadeesh (1990), and a vector autoregression (VAR) as in Campbell and Shiller (1988), Kandel and Stambaugh (1988), and Campbell (1991).

Alternative ways of conducting inference and measurement for long-horizon forecasting are explored with an application to dividend yields as predictors of stock returns. Monte Carlo analysis indicates that the Hansen and Hodrick (1980) procedure is biased at long horizons, but the alternatives perform better. These include an estimator derived under the null hypothesis as in Richardson and Smith (1991), a reformulation of the regression as in Jegadeesh (1990), and a vector autoregression (VAR) as in Campbell and Shiller (1988), Kandel and Stambaugh (1988), and Campbell (1991).

This paper documents that firms face upward-sloping supply curves when they repurchase shares in a Dutch auction, and it analyzes the market reaction to these offers. The announcement price increase is highly correlated with the ultimate repurchase premium. Prices decline at expiration only for pro-rated offers. The cumulative return is positive and highly correlated with the repurchase premium, excepting pro-rated offers. Much of this price increase is consistent with movement along an upward-sloping supply curve. Trading volume around the Dutch auction parallels fixed-price repurchasses.

This article examines how organizations participate in shaping the cultural environments of the nations that they inhabit. Cultural environments, we argue, emerge in a primarily unintended fashion as a consequence of routine, network interactions among organizations in four overlapping yet analytically distinct sectors: government, the mass media, educational institutions, and the business community. Differences in the structure of these national networks condition dynamic patterns of change in nations' cultural environments.

We analyze gated, exhaustive service of an infinite-server system with vacations. Customers enter a queue in a Poisson stream. The servers, working in parallel, serve customers in stages. A stage begins with all customers transferred from the queue to the servers (the gate opens). The servers then begin serving these customers, all simultaneously. The stage ends when their services are completed. Service is exhaustive because the servers must again examine the queue to see if any new customers arrived during the last stage. If there are any, a new stage begins.

A signalling hypothesis of leveraged buyout (LBO) capital structure is examined, wherein the promoters of an LBO unambiguously convey their commitment to generate and distribute free cash flow to investors by assuming debt service obligations high enough to exhaust free cash flow during the initial phase of the LBO operation. The signalling equilibrium results in an equity value consistent with the promoters' expectations concerning free cash flow and permits them to keep the value released by the LBO.

This paper concerns dynamic part dispatch decisions in electronic test systems with random yield. A discrete time, multiproduct, miltistage production system is used as a model for the test system with the objective to minimize the sum of inventory holding, backlogging, and overtime costs over a finite horizon. Exact results for such systems have been limited to either single-stage, multiple time period, or multistage, single time period problems with a single product. Here we develop two approximate policies: the linear decision rule, and the myopic resource allocation.

This article outlines research developments that reconcile both fundamental analysis and accounting measurement to the modern theory of valuation. Three features of accounting suggest it may play a role. First, it has the nominal attributes of a value measurement system. The financial accounting process is focused on tracking the book value of equity or net worth. The final entry in the periodic accounting cycle is the close to book values.