Robustness to the unavailability of data in block designs

We present general results for finding or boundingt _maxB , the maximum number of arbitrary whole blocks of observations which can be removed from a block design, and still leave all of the elementary treatment contrasts estimable. The block sizes may be larger than the number of treatments. The results are applied to BBDs, reinforced BIBDs and BBDs, BTIBDs, and a series of variance balanced incomplete block designs with two block sizes. Also given for most of these designs, are results fort _max, the maximum number of arbitrary, scattered observations that can become unavailable, and still leave all of the elementary treatment contrasts estimable.The work was undertaken while Dr. Whittinghill was visiting Ohio State University, and supported by a grant from the Natural Sciences Division, Colby College, Waterville, Maine.     

The impact of capacity expansion on the market value of the firm

This paper empirically investigates the impact of capacity expansion decisions on the market value of the firm. Event study methodology is used to estimate the abnormal change in stock prices around capacity expansion decision announcements. On the day of the announcement, the magnitude of the price change is abnormally high, evidenced by a significantly positive mean standardized square of the abnormal change (Beaver's U-statistic). We also analyze factors that we could affect the direction and magnitude of the abnormal change in the stock prices. We find that the change in price on the day of the announcement is positively and significantly related to the real growth rate of the industry, and negatively and significantly related to the variability of demand. A negative relationship between the price change and industry capacity utilization is also found which can have important implications for companies which follow the wait-and-see approach to capacity expansion decisions. We also find management ownership to be a significant predictor in explaining stock price changes around these announcements.     

A comparison of approximately optimal stratification given proportional allocation with other methods of stratification and allocation

Summary In this article, we shall present an approximately optimal method for constructing stratum boundary points when the sample is allocated proportionally. The method is based on an equal partitioning of the cumulative off ^1/3, wheref is the distribution of the stratification variable. We show that in many practical situations this technique compares favourably with approximately optimal stratification and allocation methods previously suggested.

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Zusammenfassung In diesem Artikel stellen wir eine annähernd optimale Methode zur Festlegung von Stratabegrenzungspunkten dar, die für proportional angeordnete Samples gilt. Die Methode basiert auf einer gleichen Einteilung derf ^1/3-Kummulation, wobeif die Verteilung der Stratifikations-variablen darstellt. Wir zeigen, daß diese Technik in vielen praktischen Fällen gegenüber den bisher vorgeschlagenen Methoden zur optimalen Stratifikation und Zuordnung nicht schlecht abschneidet.

     

Two-settlement Systems for Electricity Markets under Network Uncertainty and Market Power

We analyze welfare and distributional properties of a two-settlement system consisting of a spot market over a two-node network and a single energy forward contract. We formulate and analyze several models which simulate joint dispatch of energy and transmission resources coordinated by a system operator. The spot market is subject to network uncertainty, which we model as a random capacity derating of an important transmission line. Using a duopoly model, we show that even for small probabilities of congestion (derating), forward trading may be substantially reduced, and the market power mitigating effect of forward markets (as shown in Allaz and Vila 1993) may be nullified to a great extent. There is a spot transmission charge reflecting transportation costs from location of generation to a designated hub whose price is the underlying for the forward contract. This alleviates some of the incentive problems associated with the forward market in which spot-market trading is residual. We find that the reduction in forward trading is due to the segregation of the markets in the constrained state, and the absence of natural incentives for generators to commit to more aggressive behavior in the spot market (the strategic substitutes effect). In our analysis, we find that the standard assumption of no-arbitrage across forward and spot markets leads to very little contract coverage, even for the case with no congestion. We present an alternative view of the market where limited intertemporal arbitrage enables temporal price discrimination by competing duopolists. In this framework, we assume that all of the demand shows up in the forward market (or that the market is cleared against an accurate forecast of the demand), and the forward price is determined using a market clearing condition.     

Priority Network Access Pricing for Electric Power

We propose a priority-pricing scheme for zonal access to the electric power grid that is uniform across all buses in a zone. The independent system operator (ISO) charges bulk power traders a per unit ex ante transmission access fee. The zonal access fee serves as an access insurance premium that entitles a bulk power trader to either physical injection of one unit of energy or a compensation payment. The access fee per MWh depends on the injection zone and a self-selected strike price that serves as an insurance deductible that determines the scheduling priority of the insured transaction and the compensation level in case of curtailment. Inter-zonal transactions are charged (or credited) with an additional ex post congestion fee equal to the differences in zonal spot prices. The compensation for curtailed transactions equals the difference between the realized zonal spot price and the selected strike price (deductible level). The ISO manages congestion so as to minimize net compensation payments and thus, curtailment probabilities increase with strike price and for any particular strike price may vary from bus to bus. We calculate the rational expectations equilibrium for three-, four- and six-node systems and demonstrate that the efficiency losses of the proposed second best scheme relative to the efficient dispatch solutions are modest.     

Finding a lasting cure for U.S. health care

In "Making Competition in Health Care Work" (July-August 1994), Elizabeth Olmsted Teisberg, Michael E. Porter, and Gregory B. Brown ask a question that has been absent from the national debate on health care reform: How can the United States achieve sustained cost reductions while at the same time maintaining quality of care? The authors argue that innovation driven by rigorous competition is the key to successful reform. A lasting cure for health care in the United States should include four basic elements: corrected incentives to spur productive competition, universal insurance to secure economic efficiency, relevant information to ensure meaningful choice, and innovation to guarantee dynamic improvement. In this issue's Perspectives section, eleven experts examine the current state of the health care system and offer their views on the shape that reform should take. Some excerpts: "On the road to innovation, let us not forget to develop the tools that allow physicians, payers, and patients to make better decisions." I. Steven Udvarhelyi; "Health care is not a product or service that can be standardized, packaged, marketed, or adequately judged by consumers according to quality and price." Arnold S. Relman; "Just as antitrust laws are the wise restraints that make competition free in other sectors of the economy, so the right kind of managed competition can work well in health care." Edward M. Kennedy "Biomedical research should be considered primarily an investment in the national economic well-being with additional humanitarian benefits." Elizabeth Marincola.     

When an executive defects

The news that one of the company's senior managers is leaving comes as a complete surprise to Paul Simmonds, CEO of Kinsington Textiles, Inc. Ned Carpenter, KTI's vice president of operations for three years, writes in his resignation letter than he is leaving for a better opportunity. Simmonds soon learns that Carpenter's new job is at Daltex, one of KTI's main rivals in the intensely competitive carpet industry. Hiring Carpenter had helped Simmonds establish his reputation as a topnotch manager. Carpenter came to KTI with lots of ideas and put his enthusiasm to good use. Three years into a five-year change program, Carpenter had turned KTI's operations from one of the worst in the industry to one of the best. He also had helped develop and plan the upcoming launch of a new fiber coating--KTI's first breakthrough in years. In this fictitious case study, Simmonds, along with the company's counsel and vice president of human resources, must figure out how much and what sort of damage control they need. What are they going to tell the company's employees and the media? Should they immediately replace Carpenter with John Brady, the second-in-command of operations? What if Carpenter is taking KTI employees--and strategic information--with him to Daltex? Should Simmonds ask all his managers to sign noncompete agreements-something Carpenter was never asked to do? Should KTI sue Carpenter? Five experts offer advice about communicating with KTI's employees, the media, and Carpenter himself, and about protecting the company's confidential information.     

Employee benefit packages for part-time workers

To successfully recruit and retain part-time workers in the decade ahead, managers will need to design more attractive employee benefit packages. This article examines which benefits part-time workers receive and value the most and which benefits they would like to receive.