Complementarities and differences in adoption: an application of hazard models to two technologies in Madagascar

This paper explores the adoption of two agricultural technologies, how their patterns of adoption differ, and the relationship between them. The first technology, the System of Rice Intensification, has been studied previously and high rates of disadoption were observed in some areas. The second technology is off-season cropping, the practice of growing crops (primarily potatoes) in the rice fields during the winter season after the rice harvest. The rates of adoption of off-season cropping were much higher than for SRI and very little disadoption was observed. Through this study we are trying to understand the factors that might explain the differences in adoption and how the adoption of and experience with one technology affects the likelihood of adoption of the other. Our analysis uses hazard models, which have only recently been applied to technology adoption. Findings suggest that both methods increase the likelihood of adopting the other, and off-season crop adopters were less likely to disadopt SRI. Liquidity constraints appear to be more of an obstacle to SRI adoption, suggesting that this might help explain the relative success of off-season cropping.technology adoption, hazard models, Food Security and Poverty, International Development,

Using Linked Household-level Datasets to Explain Consumer Response to BSE in Canada

Household-level Canadian meat purchases from 2002-2008, household-level egg purchases from 2002-2005 and Food Opinion Survey in 2008 were used to understand how consumers who have different concerns about nutrition react to BSE events and how beef consumption after BSE discoveries were shaped by consumers concerns of food safety and their trust of government and the industry decision makers. Three measures of beef purchased were used to explore consumers’ reaction. A random effects logit model was applied to test whether any beef purchased during a given month. Consumption in terms of unit purchases was measured with a random effects Negative Binomial model and consumption in terms of beef expenditure was measured with a standard random effects model. Consumer behaviors in Alberta differed from Ontario. Consumer reactions to BSE in Alberta were stronger than Ontario. Overall, the more risk consumers attached to BSE, the less beef they purchased in both provinces. Random effects in the three models controlled for unobserved but persistent aspects of households and changed the sign of estimated effects of demographic variables.BSE, mad cow disease, food safety, consumer behavior, Canada, Agribusiness, Agricultural and Food Policy, Consumer/Household Economics, Food Consumption/Nutrition/Food Safety, Marketing,

How Policy Variables Influence the Timing of Social Security Disability Insurance Applications - Policy Brief

While the onset of a health based work limitation will affect a worker’s ability to remain on the job, it does not necessarily result in a swift and certain job exit and transition onto the disability rolls. The decision to leave the workforce and apply for SSDI benefits can be influenced both positively and negatively by policy variables. These two policy thrusts—SSDI transfers to replace lost earnings and accommodation to increase duration on the job—can send mixed signals to workers who experience the onset of a disability. Hence, understanding how such policies influence behavior for those who experience a disability is critical in developing policies that fully integrate people with disabilities into the workforce

Maximum Score Estimates of the Determinants of Residential Mobility: Implications for the Value of Residential Attachment and Neighborhood Amenities

This paper examines the determinants of the decision of low-income renters to move out of their current dwelling. Maximum score estimation is shown t be superior to ordinary discrete choice estimation techniques (probit, logit) for this problem, ad for similar discrete choices that require revering a previously optimal decision. The estimation reveals psychological costs of moving for typical low income renters of at least 8 percent of their income; these costs are even higher for older, longer tenure, or minority households. Policies that displace low income renters will have large social costs. In addition, the estimation results are used to calculate implicit household willingness to pay (WTP) for neighborhood amenities. This WTP based on mobility behavior is much greater than WTP estimates derived using hedonic methods, and is argued to be more accurate. This paper uses a semiparametric empirical technique to estimate the determinants of the decision of low-income renters to move out of their dwelling. These estimates show that low-income residents highly value remaining in their dwelling. In addition, these estimates are used to illustrate an alternative method to measure willingness to pay for neighborhood amenities. Moving decisions are usually examined with standard discrete choice models such as probit or logit (e.g., Venti and Wise (1984), or Weinberg, Friedman, and Mayo (1981). But the moving decision presents econometric difficulties for standard discrete choice models. As will be explained in section 1, because the household decision about moving is conditional on having previously preferred the original location, the disturbance term in mobility models is unlikely to follow the simple distributional forms required for probit or logit estimation. Maximum score estimation is an alternative estimation technique for discrete choice models that is robust to unusual distributions of the disturbance term. Although the theoretical properties of maximum score estimation have been well-explored (see Manski (1975,1985)), our paper presents one of the first empirical applications of maximum score techniques. Maximum score estimation of our residential mobility model yields similar parameter estimates to probit estimation, but much smaller standard errors. This advantage of greater precision may prove attractive to other researchers. We use our estimates of the residential mobility model to calculate the value to households of remaining at their current dwelling rather than being forced to move out. We use the household's mobility response to rent changes to infer a monetary value of remaining in the current dwelling. Our calculations indicate that the typical low-income renter household is willing to pay at least 8 percent of its annual income to avoid being forced out of its current dwelling. These "psychological moving costs" increase greatly for older or longer tenure households. Large "psychological moving costs" have important implications for public policy towards low-income neighborhoods. Neighborhood improvement policies or private market forces may displace low-income renters. If the losses suffered by low-income renters due to being forced out of their current dwelling unit are significant, as indicated in this paper, then it is important to include these losses in any evaluation of the net benefits of a neighborhood improvement program. In addition, policy makers might want to consider policies to prevent or compensate for privately-induced displacement. Estimates of the monetary value of low-income renters' psychological moving costs are important to determining the effects of these policies, and deciding appropriate compensation. Finally, this paper uses the residential mobility estimates to infer the willingness t pay (WTP) of low-income renters for neighborhood amenities such as the physical condition of the neighborhood, neighborhood school quality, and the safety of the neighborhood from crime. The relative responsiveness of household mobility to changes in these neighborhood amenities, versus changes in rents, implicitly reveals households' monetary valuations of these amenities. The more common approach to measuring household WTP for neighborhood amenities is the hedonic price approach, which relies n the equilibrium relationship between housing prices and amenities. The calculations in this paper suggest that mobility-based WTP estimates for amenities may often be greater than hedonic based estimates of WTP. We consider which approach is more accurate. Section 1 of the paper presents our econometrics, specification, and data. Section 2 presents the results. Section 3 is the conclusion.residential, mobility, determinants, Bartik, low-income, renters

The timing of disability insurance application: a choice-based semiparametric hazard model

We use a choice-based subsample of Social Security Disability Insurance applicants from the 1978 Social Security Survey of Disability and Work to test the importance of policy variables on the timing of application for disability insurance benefits following the onset of a work limiting health condition. We correct for choice-based sampling by extending the Manski-Lerman (1977) correction to the likelihood function of our continuous time hazard model defined with semiparametric unmeasured heterogeneity and find that this correction significantly affects the results. We find that economic variables-the size of the disability benefit, expected wage earnings and accommodation-matter.Insurance ; Social security

'When I click "ok" I become Sassy – I become a girl.' Young people and gender identity: Subverting the ‘body’ in massively multi-player online role-playing games

This article is available open access through the publisher’s website through the link below. Copyright @ 2012 Taylor & Francis.This article explores young people's practices in the virtual spaces of online gaming communities. Based on a five-year ethnographic study of virtual worlds, it considers how young people construct and maintain identities within virtual social systems. In particular, the article discusses digital gender practices and considers the potential that these games offer for their young users to engage in alternate gender identities. We argue that these digital spaces offer spaces for the imagination and can enhance agency and, potentially, resistance. However, digital identity is simultaneously no ‘liberated space’ and it incorporates norms and practices that often mirror those of the material world. We argue that this ‘porosity’ is an important tool through which young people come to understand gender identity

The Importance of Employer Accommodation on the Job Duration of Workers with Disabilities: A Hazard Model Approach

In line with policies long in place in Western Europe, United States disability policy is now attempting to intervene directly in the labor market to increase the employment of people with disabilities. Beginning in July, 1992, the Americans with Disabilities Act of 1990 required employers to provide reasonable accommodation to workers with disabilities. Here we use a continuous time hazard model on retrospective data from the 1978 Social Security Survey of Disability and Work to estimate the effect of employer accommodation on the subsequent job tenure of workers who suffer a work limiting health impairment. We show that the risk of leaving one\u27s employer is significantly influenced both by accommodation and by the Social Security Disability Insurance replacement rate. Accommodation appears to be as important as a worker\u27s expected replacement rate in influencing his risk of job exit

Nonmonotonic inelastic tunneling spectra due to surface spin excitations in ferromagnetic junctions

The paper addresses inelastic spin-flip tunneling accompanied by surface spin excitations (magnons) in ferromagnetic junctions. The inelastic tunneling current is proportional to the magnon density of states which is energy-independent for the surface waves and, for this reason, cannot account for the bias-voltage dependence of the observed inelastic tunneling spectra. This paper shows that the bias-voltage dependence of the tunneling spectra can arise from the tunneling matrix elements of the electron-magnon interaction. These matrix elements are derived from the Coulomb exchange interaction using the itinerant-electron model of magnon-assisted tunneling. The results for the inelastic tunneling spectra, based on the nonequilibrium Green's function calculations, are presented for both parallel and antiparallel magnetizations in the ferromagnetic leads.Comment: 9 pages, 4 figures, version as publishe

The Chromatin Remodeler BPTF Activates a Stemness Gene-Expression Program Essential for the Maintenance of Adult Hematopoietic Stem Cells

Self-renewal and differentiation of adult stem cells are tightly regulated partly through configuration of chromatin structure by chromatin remodelers. Using knockout mice, we here demonstrate that bromodomain PHD finger transcription factor (BPTF), a component of the nucleosome remodeling factor (NURF) chromatin-remodeling complex, is essential for maintaining the population size of hematopoietic stem/progenitor cells (HSPCs), including long-term hematopoietic stem cells (HSCs). Bptf-deficient HSCs are defective in reconstituted hematopoiesis, and hematopoietic-specific knockout of Bptf caused profound defects including bone marrow failure and anemia. Genome-wide transcriptome profiling revealed that BPTF loss caused downregulation of HSC-specific gene-expression programs, which contain several master transcription factors (Meis1, Pbx1, Mn1, and Lmo2) required for HSC maintenance and self-renewal. Furthermore, we show that BPTF potentiates the chromatin accessibility of key HSC “stemness” genes. These results demonstrate an essential requirement of the chromatin remodeler BPTF and NURF for activation of “stemness” gene-expression programs and proper function of adult HSCs. Wang and colleagues show that a chromatin remodeler, BPTF, sustains appropriate functions of hematopoietic stem/progenitor cells (HSPCs). BPTF loss causes bone marrow failure and anemia. The authors further define a BPTF-dependent gene-expression program in HSPCs, which contains key HSC stemness factors. These results demonstrate an essential requirement of the BPTF-associated chromatin remodelers for HSC functionality and adult hematopoiesis