London School of Economics and Political Science

About: London School of Economics and Political Science is a education organization based out in London, United Kingdom. It is known for research contribution in the topics: Population & Politics. The organization has 8759 authors who have published 35017 publications receiving 1436302 citations.

Multilevel modelling of complex survey data

Abstract: Summary. Multilevel modelling is sometimes used for data from complex surveys involving multistage sampling, unequal sampling probabilities and stratification. We consider generalized linear mixed models and particularly the case of dichotomous responses. A pseudolikelihood approach for accommodating inverse probability weights in multilevel models with an arbitrary number of levels is implemented by using adaptive quadrature. A sandwich estimator is used to obtain standard errors that account for stratification and clustering. When level 1 weights are used that vary between elementary units in clusters, the scaling of the weights becomes important. We point out that not only variance components but also regression coefficients can be severely biased when the response is dichotomous. The pseudolikelihood methodology is applied to complex survey data on reading proficiency from the American sample of the ‘Program for international student assessment’ 2000 study, using the Stata program gllamm which can estimate a wide range of multilevel and latent variable models. Performance of pseudo-maximumlikelihood with different methods for handling level 1 weights is investigated in a Monte Carlo experiment. Pseudo-maximum-likelihood estimators of (conditional) regression coefficients perform well for large cluster sizes but are biased for small cluster sizes. In contrast, estimators of marginal effects perform well in both situations. We conclude that caution must be exercised in pseudo-maximum-likelihood estimation for small cluster sizes when level 1 weights are used.

The Evolution of International Security Studies

Abstract: International Security Studies (ISS) has changed and diversified in many ways since 1945. This book provides the first intellectual history of the development of the subject in that period. It explains how ISS evolved from an initial concern with the strategic consequences of superpower rivalry and nuclear weapons, to its current diversity in which environmental, economic, human and other securities sit alongside military security, and in which approaches ranging from traditional Realist analysis to Feminism and Post-colonialism are in play. It sets out the driving forces that shaped debates in ISS, shows what makes ISS a single conversation across its diversity, and gives an authoritative account of debates on all the main topics within ISS. This is an unparalleled survey of the literature and institutions of ISS that will be an invaluable guide for all students and scholars of ISS, whether traditionalist, ‘new agenda’ or critical. • The first book to tell the post-1945 story of International Security Studies and offer an integrated historical sociology of the whole field • Opens the door to a long-overdue conversation about what ISS is and where it should be going • Provides a detailed institutional account of ISS in terms of its journals, departments, think tanks and funding sources

Cost of an emerging epidemic: an economic analysis of atrial fibrillation in the UK

Abstract: Objective: To evaluate the cost of atrial fibrillation (AF) to health and social services in the UK in 1995 and, based on epidemiological trends, to project this estimate to 2000. Design, setting, and main outcome measures: Contemporary estimates of health care activity related to AF were applied to the whole population of the UK on an age and sex specific basis for the year 1995. The activities considered (and costs calculated) were hospital admissions, outpatient consultations, general practice consultations, and drug treatment (including the cost of monitoring anticoagulant treatment). By adjusting for the progressive aging of the British population and related increases in hospital admissions, the cost of AF was also projected to the year 2000. Results: There were 534 000 people with AF in the UK during 1995. The “direct” cost of health care for these patients was £244 million (~€350 million) or 0.62% of total National Health Service (NHS) expenditure. Hospitalisations and drug prescriptions accounted for 50% and 20% of this expenditure, respectively. Long term nursing home care after hospital admission cost an additional £46.4 million (~€66 million). The direct cost of AF rose to £459 million (~€655 million) in 2000, equivalent to 0.97% of total NHS expenditure based on 1995 figures. Nursing home costs rose to £111 million (~€160 million). Conclusions: AF is an extremely costly public health problem.

Trade Credit: Suppliers as Debt Collectors and Insurance Providers

Abstract: There are two fundamental puzzles about trade credit: why does it appear to be so expensive, and why do input suppliers engage in the business of lending money? This paper addresses and answers both questions analysing the interaction between the financial and the industrial aspects of the supplier-customer relationship. It examines how, in a context of limited enforceability of contracts, suppliers may have a comparative advantage over banks in lending to their customers because they hold the extra threat of stopping the supply of intermediate goods. Suppliers may also act as liquidity providers, providing insurance against liquidity shocks that may endanger the survival of their customer relationships. The relatively high implicit interest rates of trade credit result from the existence of insurance and default premia. The implications of the model are examined empirically using parametric and nonparametric techniques on a panel of UK firms.