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Regression Metamodels for Simulation with Common Random Numbers: Comparison of Validation Tests and Confidence Intervals

Management Science 1992 38(8), 1164-1185
Linear regression analysis is important in many fields. In the analysis of simulation results, a regression (meta)model can be applied, even when common pseudorandom numbers are used. To test the validity of the specified regression model, Rao (1959) generalized the F statistic for lack of fit, whereas Kleijnen (1983) proposed a cross-validation procedure using a Student's t statistic combined with Bonferroni's inequality. This paper reports on an extensive Monte Carlo experiment designed to compare these two methods. Under the normality assumption, cross-validation is conservative, whereas Rao's test realizes its nominal type I error and has high power. Robustness is investigated through lognormal and uniform distributions. When simulation responses are distributed lognormally, then cross-validation using Ordinary Least Squares is the only technique that has acceptable type I error. Uniform distributions give results similar to the normal case. Once the regression model is validated, confidence intervals for the individual regression parameters are computed. The Monte Carlo experiment compares several confidence interval procedures. Under normality, Rao's procedure is preferred since it has good coverage probability and acceptable half-length. Under lognormality, Ordinary Least Squares achieves nominal coverage probability. Uniform distributions again give results similar to the normal case.

Simulation Designs for Quadratic Response Surface Models in the Presence of Model Misspecification

Management Science 1992 38(12), 1765-1791
This article considers the selection of experimental designs for the estimation of second-order response surface metamodels in a simulation environment. Rather than construct designs based on the premise that the postulated model exactly represents the simulated response, as is the case in optimal design theory, we assume that the estimation process may be biased by the presence of unfitted third-order terms. We therefore seek to specify experimental plans that address the bias due to possible model misspecification as well as traditional variance considerations. The performance measure used for this “fit-protect” scenario is Box and Draper's design criterion of average mean squared error of predicted response. Four important classes of response surface experimental plans are examined: (1) central composite designs, (2) Box-Behnken plans, (3) three-level factorial experiments, and (4) small central composite designs. Each design class is studied in conjunction with three pseudorandom number assignment strategies: (1) the use of a unique set of streams at each design point; (2) the assignment of a common stream set to all experimental points: and (3) the simultaneous use of common and antithetic streams through design blocking. Comparisons of both design classes and assignment strategies are presented to assist the user in the selection of an appropriate experimental strategy.

Managing I/S Design Teams: A Control Theories Perspective

Management Science 1992 38(6), 757-777
The control relationship between project managers and team members is a central aspect of the working of any Information System (I/S) design team. This paper combines research on managerial control and team-member control in order to explore a range of control behaviors that can affect the performance of an I/S design team. Measures are developed and validated for managerial control and team-member control from both an outcome and a process perspective. Results from a study of 41 actual I/S design teams indicate that high-performing teams exhibit high process control by managers and high outcome control by team members. The results also support the proposition that both managerial and team-member control coexists and that increases in the total level of control behavior is positively correlated with performance.

Vector Computers, Monte Carlo Simulation and Regression Analysis: An Introduction

Management Science 1992 38(2), 170-181
Vector computers provide a new tool for management scientists. The application of that tool requires thinking in vector mode. This mode is examined in the context of Monte Carlo experiments with regression models; these regression models may serve as metamodels in simulation experiments. The vector mode needs to exploit a specific dimension of the Monte Carlo experiment, namely the replicates of that experiment. Taking advantage of the machine architecture gives a code that computes Ordinary Least Squares estimates on a Cyber 205 in only 2% of the time needed on a Vax 8700. For Generalized Least Squares estimates, however, the code runs slower on the Cyber 205 than on the VAX, if the regression model is small; for large models the CYBER 205 runs much faster.

Top Team Deterioration as Part of the Downward Spiral of Large Corporate Bankruptcies

Management Science 1992 38(10), 1445-1466
This exploratory study of 57 large bankruptcies and 57 matched survivors examined the top management team (TMT) characteristics associated with major corporate failure. Prior research was used to guide selection of specific team characteristics for study. Not only did the failing firms show significant annual, or cross-sectional, divergence from survivors on several indicators of TMT composition, but also those divergences became more pronounced, even accelerating, over the last five years of the bankrupts' lives. The results thus suggest that deterioration of the top management team is a central element of the downward spiral of large corporate failures. Based upon a limited test of causality, the authors propose that a two-way process is at work: (1) team deficiencies bring about or aggravate corporate deterioration, either through strategic errors or stakeholder uneasiness with the flawed team; and (2) corporate deterioration brings about team deterioration, through a combination of voluntary departures, scapegoating, and limited resources for attracting new executive talent.

Growth Versus Security in Dynamic Investment Analysis

Management Science 1992 38(11), 1562-1585
This paper concerns the problem of optimal dynamic choice in discrete time for an investor. In each period the investor is faced with one or more risky investments. The maximization of the expected logarithm of the period by period wealth, referred to as the Kelly criterion, is a very desirable investment procedure. It has many attractive properties, such as maximizing the asymptotic rate of growth of the investor's fortune. On the other hand, instead of focusing on maximal growth, one can develop strategies based on maximum security. For example, one can minimize the ruin probability subject to making a positive return or compute a confidence level of increasing the investor's initial fortune to a given final wealth goal. This paper is concerned with methods to combine these two approaches. We derive computational formulas for a variety of growth and security measures. Utilizing fractional Kelly strategies, we can develop a complete tradeoff of growth versus security. The theory is applicable to favorable investment situations such as blackjack, horseracing, lotto games, index and commodity futures and options trading. The results provide insight into how one should properly invest in these situations.

A Lagrangean Relaxation Approach for Very-Large-Scale Capacitated Lot-Sizing

Management Science 1992 38(9), 1329-1340
In this paper, we develop a Lagrangean relaxation-based heuristic procedure to generate near-optimal solutions to very-large-scale capacitated lot-sizing problems (CLSP) with setup times and limited overtime. Our computational results show that large problems involving several thousand products and several thousand 0/1 integer variables can be solved in a reasonable amount of computer time to within one percent of their optimal solution. The proposed procedure is general enough to be applied directly or with slight modification to real-life production problems.

Multiple Criteria Decision Making, Multiattribute Utility Theory: The Next Ten Years

Management Science 1992 38(5), 645-654
Management science and decision science have grown exponentially since midcentury. Two closely-related fields central to this growth are multiple criteria decision making (MCDM) and multiattribute utility theory (MAUT). This paper comments on the history of MCDM and MAUT and discusses topics we believe are important in their continued development and usefulness to management science over the next decade. Our aim is to identify exciting directions and promising areas for future research.