3,145 research outputs found
Estimating the Causal Effects of Marketing Interventions Using Propensity Score Methodology
Propensity score methods were proposed by Rosenbaum and Rubin [Biometrika 70
(1983) 41--55] as central tools to help assess the causal effects of
interventions. Since their introduction more than two decades ago, they have
found wide application in a variety of areas, including medical research,
economics, epidemiology and education, especially in those situations where
randomized experiments are either difficult to perform, or raise ethical
questions, or would require extensive delays before answers could be obtained.
In the past few years, the number of published applications using propensity
score methods to evaluate medical and epidemiological interventions has
increased dramatically. Nevertheless, thus far, we believe that there have been
few applications of propensity score methods to evaluate marketing
interventions (e.g., advertising, promotions), where the tradition is to use
generally inappropriate techniques, which focus on the prediction of an outcome
from background characteristics and an indicator for the intervention using
statistical tools such as least-squares regression, data mining, and so on.
With these techniques, an estimated parameter in the model is used to estimate
some global ``causal'' effect. This practice can generate grossly incorrect
answers that can be self-perpetuating: polishing the Ferraris rather than the
Jeeps ``causes'' them to continue to win more races than the Jeeps
visiting the high-prescribing doctors rather than the
low-prescribing doctors ``causes'' them to continue to write more
prescriptions. This presentation will take ``causality'' seriously, not just as
a casual concept implying some predictive association in a data set, and will
illustrate why propensity score methods are generally superior in practice to
the standard predictive approaches for estimating causal effects.Comment: Published at http://dx.doi.org/10.1214/088342306000000259 in the
Statistical Science (http://www.imstat.org/sts/) by the Institute of
Mathematical Statistics (http://www.imstat.org
International labou's Y2K problem : a debate, a discussion and a dialogue : (a contribution to the ILO/ICFTU Conference on Organised Labour in the 21st Century)
The Institute of Social Studies is Europe's longest-established centre of higher education and research in development studies. Post-graduate teaching programmes range from six-week diploma courses to the PhD programme. Research at ISS is fundamental in the sense of laying a scientific basis for the formulation of appropriate development policies. The academic work of ISS is disseminated in the form of books, journal articles, teaching texts, monographs and working papers. The Working Paper series provides a forum for work in progress which seeks to elicit comments and generate discussion. The series includes the research of staff, PhD participants and visiting fellows, and outstanding research papers by graduate students. For further information contact
Communist Theory in the Nigerian Trade Union Movement
The subject of this paper is the Nigerian Trade Union Congress (NTUC), the Communist trade union organisation in Nigeria. More specifically, it is about the central leadership of the NTUC, since the organisation is in origin and structure a central, national and Lagos-based federation of trade unions. Even more specifically, it concerns the theoretical activity of this group, its view of Nigerian society and its organisational strategy. While this focus might seem excessively narrow for the study of a trade union organisation, it is perhaps justified for examination of a Marxist-oriented group. A true understanding of their environment has traditionally been considered a prerequisite of effective political action by Marxists. And Marxists working in the trade unions have traditionally paid great attention to organisational strategy
Union organisations, social movements and the Augean stables of global governance
The traditional international union organisations are currently engaged in a series of 'social partnership' initiatives at global level. Prominent amongst these is that addressed to 'global governance'. This project comes from outside and above the unions, is addressed to the existing hegemonic interstate instances, and is carried out primarily by lobbying. This orientation is increasingly challenged by a 'global justice and solidarity movement', more concerned with the democratisation of the global, and more oriented to consciousness-raising and mobilising than lobbying. The new movement, moreover, operates in places and spaces, with forms and understandings, that relate rather to a contemporary globalised-informatised capitalism than to the old national-industrial-colonial one which gave rise and shape to the international unions. Trade unions will have to abandon the discourse of global governance for that of global democracy, and to operate on the terrains of this new movement, if they are to effectively defend and advance worker rights and power under the new global despensation
The Bamako Appeal of Samir Amin: a post modern Janus?
The Bamako Appeal is an attempt to move the World Social Forum process from being some kind of agora for discussion of alternatives to neo-liberal globalisation, to the provision of an anti-capitalist leadership for the global justice and solidarity movement. Sponsored by prominent left activist intellectuals of the 'Thirdworldis' tradition, it has nonetheless adopted much of the language of the new movement. Because of its authors' apparent vanguardism, the BA has proven controversial within and around the leadership of the WSF. Such charters, declarations and manifestos are, however, common within the wider movement, occur within the WSF itself and should be welcomed. But the process by which the BA has appeared and been launched reproduces old movement practices that the new movement has been surpassing. The BA's chapter on labour suggests the possibility and necessity for a meaningfully global and open dialogue on the BA more generally. Whilst the BA is commonly seen as a deviation from or opposition to the WSF process, both of these instances reveal the simultaneous backward-looking and forward-looking nature of emancipatory movements
Quantification of the differences between quenched and annealed averaging for RNA secondary structures
The analytical study of disordered system is usually difficult due to the
necessity to perform a quenched average over the disorder. Thus, one may resort
to the easier annealed ensemble as an approximation to the quenched system. In
the study of RNA secondary structures, we explicitly quantify the deviation of
this approximation from the quenched ensemble by looking at the correlations
between neighboring bases. This quantified deviation then allows us to propose
a constrained annealed ensemble which predicts physical quantities much closer
to the results of the quenched ensemble without becoming technically
intractable.Comment: 9 pages, 14 figures, submitted to Phys. Rev.
Reflections on the 2nd World Social Forum in Porto Alegre : what's left internationally?
This paper reflects on the implications for the international trade union movementand Left of the 60-70,000-strong World Social Forum II. The reflections concern the analytical, theoretical and strategic implications of and for this first major internationalmovement of the era of a globalized and informatized capitalism. Considered in turn are: 1.The Forum's Charter and the Call of Social Movements issued from it; 2. The impact of theForum on the Left as an 'old social movement'; 3. Its implications for feminism as a 'newsocial movement'; 4. The meaning of 'Left' in the light of the Forum; 5. The strategy problem the unions still imply for the global justice movement; 6. The necessity of moving themovement away from an organizational and toward a communicational logic; 7. The needfor a political-economy of global civil society construction. The Conclusion reflects on theconcept of revolution in the era of capitalist globalization, as well as the role of the globaljustice movement in surpassing the emancipatory model of the French Revolution
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