London School of Economics and Political Science

This paper presents specification tests that are applicable after estimating a dynamic model from panel data by the generalized method of moments (GMM), and studies the practical performance of these procedures using both generated and real data. Our GMM estimator optimally exploits all the linear moment restrictions that follow from the assumption of no serial correlation in the errors, in an equation which contains individual effects, lagged dependent variables and no strictly exogenous variables. We propose a test of serial correlation based on the GMM residuals and compare this with Sargan tests of over-identifying restrictions and Hausman specification tests.

The goal of the International HapMap Project is to determine the common patterns of DNA sequence variation in the human genome and to make this information freely available in the public domain. An international consortium is developing a map of these patterns across the genome by determining the genotypes of one million or more sequence variants, their frequencies and the degree of association between them, in DNA samples from populations with ancestry from parts of Africa, Asia and Europe. The HapMap will allow the discovery of sequence variants that affect common disease, will facilitate development of diagnostic tools, and will enhance our ability to choose targets for therapeutic intervention.

Abstract Although economists have long been aware of Jensen's inequality, many econometric applications have neglected an important implication of it: under heteroskedasticity, the parameters of log-linearized models estimated by OLS lead to biased estimates of the true elasticities. We explain why this problem arises and propose an appropriate estimator. Our criticism of conventional practices and the proposed solution extend to a broad range of applications where log-linearized equations are estimated. We develop the argument using one particular illustration, the gravity equation for trade. We find significant differences between estimates obtained with the proposed estimator and those obtained with the traditional method.

This paper provides a framework for addressing the question of when transactions should be carried out within a firm and when through the market. Following Grossman and Hart, we identify a firm with the assets that its owners control. We argue that the crucial difference for party 1 between owning a firm (integration) and contracting for a service from another party 2 who owns this firm (nonintegration) is that, under integration, party 1 can selectively fire the workers of the firm (including party 2), whereas under nonintegration he can "fire" (i.e., stop dealing with) only the entire firm: the combination of party 2, the workers, and the firm's assets. We use this idea to study how changes in ownership affect the incentives of employees as well as those of owner-managers. Copyright 1990 by University of Chicago Press.

Summary Methods for studying the stability over time of regression relationships are considered. Recursive residuals, defined to be uncorrelated with zero means and constant variance, are introduced and tests based on the cusum and cusum of squares of recursive residuals are developed. Further techniques based on moving regressions, in which the regression model is fitted from a segment of data which is moved along the series, and on regression models whose coefficients are polynomials in time are studied. The Quandt log-likelihood ratio statistic is considered. Emphasis is placed on the use of graphical methods. The techniques proposed have been embodied in a comprehensive computer program, timvar. Use of the techniques is illustrated by applying them to three sets of data.

The authors construct a model of a dynamic economy in which lenders cannot force borrowers to repay their debts unless the debts are secured. In such an economy, durable assets play a dual role: not only are they factors of production but they also serve as collateral for loans. The dynamic interaction between credit limits and asset prices turns out to be a powerful transmission mechanism by which the effects of shocks persist, amplify, and spill over to other sectors. The authors show that small, temporary shocks to technology or income distribution can generate large, persistent fluctuations in output and asset prices. Copyright 1997 by the University of Chicago.

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In this new edition of his landmark book, Richard Layard shows that there is a paradox at the heart of our lives. Most people want more income. Yet as societies become richer, they do not become happier. This is not just anecdotally true, it is the story told by countless pieces of scientific research. We now have sophisticated ways of measuring how happy people are, and all the evidence shows that on average people have grown no happier in the last fifty years, even as average incomes have more than doubled. In fact, the First World has more depression, more alcoholism and more crime than fifty years ago. This paradox is true of Britain, the United States, continental Europe, and Japan. What is going on? Now fully revised and updated to include developments since first publication, Layard answers his critics in what is still the key book in 'happiness studies'.

In this book, Andrew Harvey sets out to provide a unified and comprehensive theory of structural time series models. Unlike the traditional ARIMA models, structural time series models consist explicitly of unobserved components, such as trends and seasonals, which have a direct interpretation. As a result the model selection methodology associated with structural models is much closer to econometric methodology. The link with econometrics is made even closer by the natural way in which the models can be extended to include explanatory variables and to cope with multivariate time series. From the technical point of view, state space models and the Kalman filter play a key role in the statistical treatment of structural time series models. The book includes a detailed treatment of the Kalman filter. This technique was originally developed in control engineering, but is becoming increasingly important in fields such as economics and operations research. This book is concerned primarily with modelling economic and social time series, and with addressing the special problems which the treatment of such series poses. The properties of the models and the methodological techniques used to select them are illustrated with various applications. These range from the modellling of trends and cycles in US macroeconomic time series to to an evaluation of the effects of seat belt legislation in the UK.

There is wide agreement about the major goals of economic policy: high employment, stable prices, and rapid growth. There is less agreement that these goals are mutually compatible or, among those who regard them as incompatible, about the terms at which they can and should be substituted for one another. There is least agreement about the role that various instruments of policy can and should play in achieving the several goals.

J. DURBIN, G. S. WATSON; TESTING FOR SERIAL CORRELATION IN LEAST SQUARES REGRESSION. II, Biometrika, Volume 38, Issue 1-2, 1 June 1951, Pages 159–178, http

This paper sets out an approach to the analysis of political power in terms of problematics of government. It argues against an overvaluation of the 'problem of the State' in political debate and social theory. A number of conceptual tools are suggested for the analysis of the many and varied alliances between political and other authorities that seek to govern economic activity, social life and individual conduct. Modern political rationalities and governmental technologies are shown to be intrinsically linked to developments in knowledge and to the powers of expertise. The characteristics of liberal problematics of government are investigated, and it is argued that they are dependent upon technologies for 'governing at a distance', seeking to create locales, entities and persons able to operate a regulated autonomy. The analysis is exemplified through an investigation of welfarism as a mode of 'social' government. The paper concludes with a brief consideration of neo-liberalism which demonstrates that the analytical language structured by the philosophical opposition of state and civil society is unable to comprehend contemporary transformations in modes of exercise of political power.(1).

Journal Article Essays in Positive Economics Get access Essays in Positive Economics. By Milton Friedman. (Chicago : University of Chicago Press (London : Cambridge University Press), 1954. Pp. v + 328. 43s. 6d.) T. W. Hutchison T. W. Hutchison London School of Economics Search for other works by this author on: Oxford Academic Google Scholar The Economic Journal, Volume 64, Issue 256, 1 December 1954, Pages 796–799, https://doi.org/10.2307/2228046 Published: 01 December 1954

This is a substantial revision of a much-quoted monograph, first published in 1974. The structure is unchanged, but the text has been clarified and the notation brought into line with current practice. A large number of 'Additional Results' are included at the end of each chapter, thereby covering most of the major advances in the last twenty years. Professor Biggs' basic aim remains to express properties of graphs in algebraic terms, then to deduce theorems about them. In the first part, he tackles the applications of linear algebra and matrix theory to the study of graphs; algebraic constructions such as adjacency matrix and the incidence matrix and their applications are discussed in depth. There follows an extensive account of the theory of chromatic polynomials, a subject which has strong links with the 'interaction models' studied in theoretical physics, and the theory of knots. The last part deals with symmetry and regularity properties. Here there are important connections with other branches of algebraic combinatorics and group theory. This new and enlarged edition this will be essential reading for a wide range of mathematicians, computer scientists and theoretical physicists.

Greenhouse gas (GHG) emissions are externalities and represent the biggest market failure the world has seen. We all produce emissions, people around the world are already suffering from past emissions, and current emissions will have potentially catastrophic impacts in the future. Thus, these emissions are not ordinary, localized externalities. Risk on a global scale is at the core of the issue. These basic features of the problem must shape the economic analysis we bring to bear; failure to do this will produce, and has produced, approaches to policy that are profoundly misleading and indeed dangerous. The purpose of this chapter is to set out what I think is an appropriate way to examine the economics of climate change, given the unique scientific and economic challenges posed, and to suggest implications for emissions targets, policy instruments, and global action. The subject is complex and very wide-ranging. It is a subject of vital importance but one in which the economics is fairly young. A central challenge is to provide the economic tools necessary as quickly as possible, because policy decisions are both urgent and moving quickly—particularly following the United Nations Framework Convention on Climate Change (UNFCCC) meetings in Bali in December 2007. The relevant decisions can be greatly improved if we bring the best economic analyses and judgments to the table in real time. A brief description of the scientific processes linking climate change to GHG emissions will help us to understand how they should shape the economic analysis. First, people, through their consumption and production decisions, emit GHGs. Carbon dioxide is especially important, accounting for around three-quarters of the human-generated global-warming effect; other relevant GHGs include methane, nitrous oxide, and hydrofluorocarbons (HFCs). Second, these flows accumulate into stocks of GHGs in the atmosphere. It is overall stocks of GHGs that matter and not their place of origin. The rate at which stock accumulation occurs depends on the “carbon cycle,” including the earth’s absorptive capabilities and other feedback effects. Third, the stock of GHGs in the atmosphere traps heat and results in global warming; how much depends on “climate sensitivity.”

This paper argues that existing models of urban concentrations are incomplete unless grounded in the most fundamental aspect of proximity; face-to-face contact. Face-to-face contact has four main features: it is an efficient communication technology; it can help solve incentive problems; it can facilitate socialization and learning; and it provides psychological motivation. We discuss each of these features in turn, and develop formal economic models of two of them. Face-to-face is particularly important in environments where information is imperfect, rapidly changing, and not easily codified, key features of many creative activities.

The ''new public management'' (NPM) wave in public sector organizational change was founded on themes of disaggregation, competition, and incentivization. Although its effects are still working through in countries new to NPM, this wave has now largely stalled or been reversed in some key ''leading-edge'' countries. This ebbing chiefly reflects the cumulation of adverse indirect effects on citizens' capacities for solving social problems because NPM has radically increased institutional and policy complexity. The character of the post-NPM regime is currently being formed. We set out the case that a range of connected and information technology-centered changes will be critical for the current and next wave of change, and we focus on themes of reintegration, needs-based holism, and digitization changes. The overall movement incorporating these new shifts is toward ''digital-era governance'' (DEG), which involves reintegrating functions into the governmental sphere, adopting holistic and needs-oriented structures, and progressing digitalization of administrative processes. DEG offers a perhaps unique opportunity to create self-sustaining change, in a broad range of closely connected technological, organizational, cultural, and social effects. But there are alternative scenarios as to how far DEG will be recognized as a coherent phenomenon and implemented successfully.

Systematic reviews are characterized by a methodical and replicable methodology and presentation. They involve a comprehensive search to locate all relevant published and unpublished work on a subject; a systematic integration of search results; and a critique of the extent, nature, and quality of evidence in relation to a particular research question. The best reviews synthesize studies to draw broad theoretical conclusions about what a literature means, linking theory to evidence and evidence to theory. This guide describes how to plan, conduct, organize, and present a systematic review of quantitative (meta-analysis) or qualitative (narrative review, meta-synthesis) information. We outline core standards and principles and describe commonly encountered problems. Although this guide targets psychological scientists, its high level of abstraction makes it potentially relevant to any subject area or discipline. We argue that systematic reviews are a key methodology for clarifying whether and how research findings replicate and for explaining possible inconsistencies, and we call for researchers to conduct systematic reviews to help elucidate whether there is a replication crisis.

This paper shows that corporate social responsibility (CSR) and firm value are positively related for firms with high customer awareness, as proxied by advertising expenditures. For firms with low customer awareness, the relation is either negative or insignificant. In addition, we find that the effect of awareness on the CSR–value relation is reversed for firms with a poor prior reputation as corporate citizens. This evidence is consistent with the view that CSR activities can add value to the firm but only under certain conditions. This paper was accepted by Bruno Cassiman, business strategy.

This is the first part of a three-volume work on the nature of power in human societies. In it, Michael Mann identifies the four principal 'sources' of power as being control over economic, ideological, military, and political resources. He examines the interrelations between these in a narrative history of power from Neolithic times, through ancient Near Eastern civilisations, the classical Mediterranean age, and medieval Europe, up to just before the Industrial Revolution in England. Rejecting the conventional monolithic concept of a 'society', Dr. Mann's model is instead one of a series of overlapping, intersecting power networks. He makes this model operational by focusing on the logistics of power - how the flow of information, manpower, and goods is controlled over social and geographical space-thereby clarifying many of the 'great debates' in sociological theory. The present volume offers explanations of the emergence of the state and social stratification