2,142 research outputs found
A three-pillar strategic framework for competing with China
China is not yet a military challenge as Russia is (or the Soviet Union was during the Cold War), but neither is it simply an economic competitor. In this article, Peter Watkins introduces a series of blog posts that LSE Business Review will be publishing along the next couple of weeks. The series summarises the new report âProtect, Constrain, Contestâ, by LSE IDEAS, the foreign policy think tank at LSE. In the report, academics and China watchers set out the important policies needed to put Western relationships with China on a firmer and more manageable footing
Social Networks, HIV/AIDS and Risk Perceptions
Understanding the determinants of individualsâ perceptions of their risk of becoming infected with HIV and their perceptions of acceptable strategies of prevention is an essential step towards curtailing the spread of this disease. We focus in this paper on learning and decision-making about AIDS in the context of high uncertainty about the disease and appropriate behavioral responses, and we argue that social interaction is an important determinant of risk perceptions and the acceptability of behavioral change. Using longitudinal survey data from rural Kenya and Malawi, we test this hypothesis. We investigate whether social interactionsâand especially the extent to which social network partners perceive themselves to be at risk âexert causal influences on respondentsâ risk perceptions and on one approach to prevention, spousal communication about the threat of AIDS to the couple and their children. The study explicitly allows for the possibility that important characteristics, such as unobserved preferences or community characteristics, determine not only the outcomes of interest but also the size and composition of networks. The most important empirical result is that social networks have significant and substantial effects on risk perception and the adoption of new behaviors even after controlling for unobserved factors.health, AIDS, information, social networks, Africa
How can we measure the causal effects of social networks using observational data? Evidence from the diffusion of family planning and AIDS worries in South Nyanza District, Kenya
This study presents estimates that social networks exert causal and substantial influences on individualsâ attitudes and behaviors. The study explicitly allows for the possibility that social networks are not chosen randomly, but rather that important characteristics such as unobserved preferences and unobserved community characteristics determine not only the outcomes of interest but also the informal conversational networks in which they are discussed. Longitudinal survey data from rural Kenya on family-planning and AIDS are used to estimate the impact of social networks while controlling for their unobserved determinants. There are four major findings: First, the endogeneity of social networks can substantially distort the usual cross-sectional estimates of network influences. Second, social networks have significant and substantial effects even after controlling for unobserved factors that may determine the nature of the social networks. Third, these network effects generally are nonlinear and asymmetric. In particular, they are relatively large for individuals who have at least one network partner who is perceived to be using contraceptives or or to be at high risk of HIV/AIDS, which is consistent with S-shaped diffusion models that have been emphasized in the literature. Fourth, the effects of networks are not confined to the use of family planning by women, the focus of much of the literature on networks in demography, but appear to be more general, influencing responses to HIV/AIDS, and influencing men as well as women. (AUTHORS)
A summary of Special Collection 1
Special Collection 1: Social Interactions and HIV/AIDS in Rural Africa is a set of papers stemming from the conference "Research on Demographic Aspects of HIV/AIDS in Rural Africa", held at the Population Studies Center, University of Pennsylvania, October 28, 2002. The aim of the conference was to provide a forum for the presentation of results, to an audience of experts, on a variety of demographic aspects relevant for the study of HIV/AIDS in rural Africa. The aim of the special collection is to make these results available to a wider audience. Thirteen contributions were submitted to the journal Demographic Research and went through peer review. They were published on September 19, 2003 as the journalâs first ĂąâŹĆspecial collectionù⏠of material on a common topic. This short summary of the collection has been added to Volume 9 in order to include full details of the collection in the current running volume as well. The following pages list the contributions and give direct links where readers may download the material from the Demographic Research website. A full list of all papers is also available at: http://www.demographic-research.org/special/1/.AIDS/HIV, Kenya, Malawi
The Malawi Diffusion and Ideational Change Project 2004-06
In this paper, we evaluate the quality of survey data collected by the Malawi Diffusion and Ideational Change Project by investigating four potential sources of bias: sample representativeness, interviewer effects, response unreliability and sample attrition. We discuss the results of our analysis and implications of our findings for the collection of data in similar contexts.AIDS/HIV, data quality, interviewer effects, representativeness, response reliability, sample attrition, Sub-Saharan Africa
Attrition in longitudinal household survey data
Longitudinal household data can have considerable advantages over much more widely used cross-sectional data. The collection of longitudinal data, however, may be difficult and expensive. One problem that has concerned many analysts is that sample attrition may make the interpretation of estimates problematic. Such attrition may be particularly severe in areas where there is considerable mobility because of migration between rural and urban areas. Many analysts share the intuition that attrition is likely to be selective on characteristics such as schooling and that high attrition is likely to bias estimates made from longitudinal data. This paper considers the extent of and implications of attrition for three longitudinal household surveys from Bolivia, Kenya, and South Africa that report very high per-year attrition rates between survey rounds. Our estimates indicate that (1) the means for a number of critical outcome and family background variables differ significantly between attritors and nonattritors; (2) a number of family background variables are significant predictors of attrition; but (3) nevertheless, the coefficient estimates for âstandardâ family background variables in regressions and probit equations for the majority of the outcome variables considered in all three data sets are not affected significantly by attrition. Therefore, attrition apparently is not a general problem for obtaining consistent estimates of the coefficients of interest for most of these outcomes. These results, which are very similar to results for developed economies, suggest that for these outcome variablesâdespite suggestions of systematic attrition from univariate comparisons between attritors and nonattritors, multivariate estimates of behavioral relations of interest may not be biased due to attrition.Household surveys Methodology ,
Attrition in longitudinal household survey data
Longitudinal household data can have considerable advantages over much more widely used cross-sectional data. The collection of longitudinal data, however, may be difficult and expensive. One problem that has concerned many analysts is that sample attrition may make the interpretation of estimates problematic. Such attrition may be particularly severe in areas where there is considerable mobility because of migration between rural and urban areas. Many analysts share the intuition that attrition is likely to be selective on characteristics such as schooling and that high attrition is likely to bias estimates made from longitudinal data. This paper considers the extent of and implications of attrition for three longitudinal household surveys from Bolivia, Kenya, and South Africa that report very high per-year attrition rates between survey rounds. Our estimates indicate that (1) the means for a number of critical outcome and family background variables differ significantly between attritors and nonattritors; (2) a number of family background variables are significant predictors of attrition; but (3) nevertheless, the coefficient estimates for âstandardâ family background variables in regressions and probit equations for the majority of the outcome variables considered in all three data sets are not affected significantly by attrition. Therefore, attrition apparently is not a general problem for obtaining consistent estimates of the coefficients of interest for most of these outcomes. These results, which are very similar to results for developed economies, suggest that for these outcome variablesâdespite suggestions of systematic attrition from univariate comparisons between attritors and nonattritors, multivariate estimates of behavioral relations of interest may not be biased due to attrition.Household surveys Methodology ,
Attrition in longitudinal household survey data - some tests for three developing-country samples
For capturing dynamic demographic relationships, longitudinal household data can have considerable advantages over more widely used cross-sectional data. But because the collection of longitudinal data may be difficult and expensive, analysts must assess the magnitudes of the problems, specific to longitudinal, but not to cross-sectional data. One problem that concerns many analysts is that sample attrition may make the interpretation of estimates problematic. Such attrition may be especially severe where there is considerable migration between rural, and urban areas. And attrition is likely to be selective on such characteristics as schooling, so high attrition is likely to bias estimates. The authors consider the extent, and implications of attrition for three longitudinal household surveys from Bolivia, Kenya, and South Africa that report very high annual attrition rates between survey rounds. Their estimates indicate that: 1) the means for a number of critical outcome, and family background variables differ significantly between those who are lost to follow-up, and those who are re-interviewed. 2) A number of family background variables are significant predictors of attrition. 3) Nevertheless, the coefficient estimates for standard family background variables in regressions, and probit equations for the majority of outcome variables in all three data sets, are not significantly affected by attrition. So attrition is apparently not a general problem for obtaining consistent estimates of the coefficients of interest for most of these outcomes. These results, which are very similar to those for industrial countries, suggest that multivariate estimates of behavioral relations may not be biased because of attrition. This wold support the collection of longitudinal data.Statistical&Mathematical Sciences,Public Health Promotion,Health Monitoring&Evaluation,Scientific Research&Science Parks,Educational Sciences,Science Education,Scientific Research&Science Parks,Health Monitoring&Evaluation,Poverty Assessment,Statistical&Mathematical Sciences
Multi-Modal Geometric Learning for Grasping and Manipulation
This work provides an architecture that incorporates depth and tactile
information to create rich and accurate 3D models useful for robotic
manipulation tasks. This is accomplished through the use of a 3D convolutional
neural network (CNN). Offline, the network is provided with both depth and
tactile information and trained to predict the object's geometry, thus filling
in regions of occlusion. At runtime, the network is provided a partial view of
an object. Tactile information is acquired to augment the captured depth
information. The network can then reason about the object's geometry by
utilizing both the collected tactile and depth information. We demonstrate that
even small amounts of additional tactile information can be incredibly helpful
in reasoning about object geometry. This is particularly true when information
from depth alone fails to produce an accurate geometric prediction. Our method
is benchmarked against and outperforms other visual-tactile approaches to
general geometric reasoning. We also provide experimental results comparing
grasping success with our method
Does globalisation face an existential threat?
The COVID-19 pandemic has been a significant shock for the global economy. With nations protecting their borders and even limiting some trade, does globalisation now face an existential threat? In reality, this is not an entirely new issue, write Michael Cox, Peter Watkins, and Linda Yueh (LSE Ideas)
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