Social scientists rarely take full advantage of the information available in their statistical results. As a consequence, they miss opportunities to present quantities that are of greatest substantive interest for their research and express the appropriate degree of certainty about these quantities. In this article, we offer an approach, built on the technique of statistical simulation, to extract the currently overlooked information from any statistical method and to interpret and present it in a reader-friendly manner. Using this technique requires some expertise,

In the context of software cost estimation, system size is widely taken as a main driver of system development effort. But, other structural design properties, such as coupling, cohesion, and complexity, have been suggested as additional cost factors. In this paper, using effort data from an object-oriented development project, we empirically investigate the relationship between class size and the development effort for a class and what additional impact structural properties such as class coupling have on effort. This paper proposes a practical, repeatable, and accurate analysis procedure to investigate relationships between structural properties and development effort. This is particularly important as it is necessary, as for any empirical study, to be able to replicate the analysis reported here. More specifically, we use Poisson regression and regression trees to build cost prediction models from size and design measures and use these models to predict system development effort. We also investigate a recently suggested technique to combine regression trees with regression analysis which aims at building more accurate models. Results indicate that fairly accurate predictions of class effort can be made based on simple measures of the class interface size alone (mean MREs below 30 percent). Effort predictions at the system level are even more accurate as, using Bootstrapping, the estimated 95 percent confidence interval for MREs is 3 to 23 percent. But, more sophisticated coupling and cohesion measures do not help to improve these predictions to a degree that would be practically significant. However, the use of hybrid models combining Poisson regression and CART regression trees clearly improves the accuracy of the models as compared to using Poisson regression alone.

“Financial Systems and Institutions in the Third Millenium ” conference (Jerusalem), and the “Emerging Markets Finance ” conference (London Business School) for very helpful comments and suggestions. Several individuals assisted us with data collection, especially Chanhi Park with the Korean data, Liat Sack with the Israeli data, and Hideaki Miyajima with the pre-war Japanese data. William Simpson contributed his invaluable econometric expertise, and Eli Enoch, Kathleen Ryan, James Schorr and Zamir Sivan assisted in assembling the database. Khanna thanks the Division of Research at HBS for financial support. All errors remain our own. Business Groups and Risk Sharing around the World Researchers commonly assume that business groups, a ubiquitous organizational form in emerging markets, permit affiliated firms to share risk by smoothing income flows and by reallocating money from one affiliate to another in times of distress. This view has received support in the literature on Japanese keiretsu. To examine the generality of these findings worldwide, we amass a new data set on business groups in 15 emerging markets, and couple this with historical and modern data from Japan. Our results, using multiple estimation techniques, corroborate the existing evidence on risk sharing within the Japanese keiretsu. In addition, in

their data. We also thank two anonymous referees for their thoughtful suggestions. Errors remain the responsibility of the authors. 2Business environment, operations strategy, and performance: An empirical study of Singapore manufacturers Consideration of the task environment, those forces which are out of the short-run control of management, has been relatively neglected in operations strategy research. The neglect of environmental factors in operations strategy research is surprising when one considers that the fit between environment and organizational capabilities and resources is a central tenet of major strategic management paradigms. We use a path analytic framework to study the effects of environment on operations strategy selection and performance (self-reported change in profits) for a sample of Singapore manufacturers. We identify strong relationships between environmental factors such as labor availability, competitive hostility, and market dynamism and the operations strategy choices encompassed by competitive priorities. The data also indicate that, when faced with the same environmental stimuli, high performers choose to emphasize different competitive priorities than low performers. In addition to exploring substantive questions about the importance of the environment in explaining operations strategy, this research also demonstrates that environmental variables can provide effective controls for industry effects in multiple industry empirical studies in operations strategy. 1.

Stata 7 is a general-purpose statistical package that does all of the textbook statistical analyses, and has a number of procedures found only in highly specialized software 1. Unlike most commercial packages aimed at making it possible for any Windows user to produce smart-looking graphs and tables, Stata is aimed primarily at researchers that possess the knowledge of the statistical tools they are using in their subject fields. The applications of statistics that are covered best by Stata are econometrics, social sciences and biostatistics. The Stata tools for the latter two categories are contignency tables, stratified and clustered survey data analysis (useful also for health and labor economists), and survival data analysis (useful also in the duration studies, such as the studies of the lengths of unemployment or poverty spells). There are several things that I like most about Stata. First of all, it is just a very good package for doing applied research, with lots of everyday estimation and testing techniques, as well as convenient data handling tools. The unified syntax makes all these things easy to use. It is also a rapidly developing package,

Abstract: The declining reliability of the US electric power system is raising major concerns amongst both politicians and power engineers in the USA. One of the reasons put forward by the North Electric Reliability Council (NERC) is the detrimental role played by the protection systems during large disturbances, which tend to help the perturbations to propagate through over-tripping of fault free system components due to hidden failures. It turns out that the present practice in power transmission planning and online security analysis is to neglect the impact of the protection systems. In addition, the aim is to mitigate the vulnerability of the system to the loss of a single piece of equipment only by carrying out an N-1 security analysis. Consequently, the risk of cascading failures leading to blackouts and brownouts is neither assessed nor managed. This paper describes methodologies together with algorithms that assess the conditional risk of catastrophic failures in electric power networks due to hidden failures in protection systems. A catastrophic failure, defined as one that results in the outage of a sizable amount of load, may be caused by dynamic instabilities in the system or exhaustion of the reserves in transmission due to a sequence of line tripping leading to voltage collapse. Only the latter case is being considered. The aim of these algorithms is to identify the weak links in the systems, which are defined as those branches of the network whose tripping due to a fault lead to the highest probabilities of a catastrophic failure. The proposed methods are demonstrated on a 7-bus and a 61-bus system.

We develop and apply a criterion to distinguish two paradigms of international trade theory: constant-returns perfectly competitive models, and increasing-returns monopolistically competitive models. Our analysis makes use of the pervasive presence of home-biased expenditure. It predicts that countries ’ relative output and their relative home biases are positively correlated in increasing-returns sectors, while no such relationship exists in constantreturns sectors. We estimate country-level sectoral home biases through a gravity equation for international and intranational trade, and we use those estimates to implement our test on inputoutput data for six European Union economies. JEL classification: Keywords: F1, R3 international specialisation, new trade theory, home-market effects, border effects

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This paper examines theory and evidence on party competition in the U. S. Congress in the allocation of members to committees. Parties allocate members to committees to maximize the joint utility of its members, taking into account how the committees' memberships affect the legislation adopted by the legislature. Parties are constrained by both institutional rules and the heterogeneity of party members' preferences. Interest group ratings from the U.S. House of Representatives provide evidence that the parties stack committees in a manner consistent with the predictions of the theoretical model. Alternative hypotheses explain no more than half the committees in the U. S. Congress, while the party competition hypothesis is consistent with the overall structure of the committees. Model selection tests that nest the party competition and representative majority party hypotheses reveal that the party competition hypothesis is supported by the data while the representative majority party hypothesis is not. The Role of Political Parties in the Organization of Congress Abstract: This paper examines theory and evidence on party competition in the U. S. Congress in the allocation of members to committees. Parties allocate members to committees to maximize the joint utility of its members, taking into account how the committees' memberships affect the legislation adopted by the legislature. Parties are constrained by both institutional rules and the heterogeneity of party members' preferences. Interest group ratings from the U.S. House of Representatives provide evidence that the parties stack committees in a manner consistent with the predictions of the theoretical model. Alternative hypotheses explain no more than half the committees in the U. S. Congress, while the party c...

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