Exploring the relationship between subjective well-being and objective poverty indices : evidence from panel data in South Africa

This study investigates the relationship between subjective well-being and objective poverty indices such as income poverty and multidimensional poverty. Although they are popular indices, very few studies have analyzed their relationship using rigorous econometric approach. By applying the Blow-up and Cluster estimation of fixed effects ordered logit model to a panel data collected in South Africa, this study finds that both income and multidimensional poverties significantly aggravate subjective well-being. However, their effects are not robust to the inclusion of household income, implying that being below the poverty lines does not provide additional information to explain subjective well-being. Moreover, a large part of the variation in subjective well-being cannot be explained by these objective poverty indices, suggesting strong complementarity between subjective and objective welfare measures. This study also finds that multidimensional poverty index, constructed based on principal component analysis, performs better than the conventional approach, casting doubt on the conventional multidimensional poverty index

Regional disparities in subjective well-being : a spatial econometric approach

This study aims to explore spatial externalities in subjective well-being (SWB) as sources of regional disparities. Although previous studies have shown positive externalities in SWB, the estimated effect is frequently confounded by unobserved regional heterogeneities, which can be sources of regional disparities. Using a household panel dataset collected in South Africa, the study estimates spatial econometric models with fixed effects to show spatial externalities in SWB by explicitly controlling for unobserved heterogeneities at the individual and regional levels. Estimation results indicate strong spatial dependence on SWB, confirming that spatial externalities within and across geographical clusters are essential factors for explaining regional disparities

灌漑、共同体、貧困

学位の種別:課程博士University of Tokyo(東京大学

Neighborhood Effects in Pesticide Use : Evidence from the Rural Philippines

This study investigates how pesticide use by neighboring farmers affects a given farmer’s pesticide use. Although it is common knowledge that pesticide use has spatial externalities, few empirical economic studies directly analyze this issue. Applying the spatial panel econometric model to the plot-level panel data in Bohol, the Philippines, this study shows that the pesticide use, especially for herbicides, is spatially correlated although there is no statistically significant spatial correlation in unobserved shocks. This implies that farmers apply pesticides by mimicking neighboring farmers’ behavior rather than rationally responding to the intensity of infestation.JEL Classification Codes: Q56, Q12, O1

Is farmer-to-farmer extension effective? The impact of training on technology adoption and rice farming productivity in Tanzania

Agricultural training is a potentially effective method to diffuse relevant new technologies to increase productivity and alleviate rural poverty in Sub-Saharan Africa (SSA). However, since it is prohibitively expensive to provide direct training to all the farmers in SSA, it is critically important to examine the extent to which technologies taught to a small number of farmers disseminate to non-trained farmers. This paper investigates the technology dissemination pathways among smallholder rice producers within a rural irrigation scheme in Tanzania. As an innovative feature, we compare the performance of three categories of farmers: key farmers, who receive intensive pre-season training at a local training center; intermediate farmers, who are trained by the key farmers; and other ordinary farmers. By collecting and analyzing a unique five-year household-level panel data set, we estimate difference-in-differences models to assess how the gap in performance evolve as the technologies spill over from the trained farmers to the ordinary farmers. To disentangle the technology spillover process, we also examine the extent to which social and geographical network with the key and intermediate farmers influences the adoption of technologies by the ordinary farmers, by incorporating social relationship variables into spatial econometric models. We found that the ordinary farmers who were a relative or residential neighbor of a key or intermediate farmer were more likely to adopt new technologies than those who were not. As a result, while the key farmers’ technology adoption rates rose immediately after the training, those of the non-trained ordinary farmers caught up belatedly. As the technologies disseminated, the paddy yield of the key farmers increased from 3.1 to 5.3 tons per hectare, while the yield of the ordinary farmers increased from 2.6 to 3.7 tons per hectare. Our results suggest the effectiveness and practical potential of farmer-to-farmer extension programs for smallholders in SSA as a cost effective alternative to the conventional farmer training approach

Effect of surgical experience and spine subspecialty on the reliability of the {AO} Spine Upper Cervical Injury Classification System

OBJECTIVE The objective of this paper was to determine the interobserver reliability and intraobserver reproducibility of the AO Spine Upper Cervical Injury Classification System based on surgeon experience (< 5 years, 5–10 years, 10–20 years, and > 20 years) and surgical subspecialty (orthopedic spine surgery, neurosurgery, and "other" surgery). METHODS A total of 11,601 assessments of upper cervical spine injuries were evaluated based on the AO Spine Upper Cervical Injury Classification System. Reliability and reproducibility scores were obtained twice, with a 3-week time interval. Descriptive statistics were utilized to examine the percentage of accurately classified injuries, and Pearson’s chi-square or Fisher’s exact test was used to screen for potentially relevant differences between study participants. Kappa coefficients (κ) determined the interobserver reliability and intraobserver reproducibility. RESULTS The intraobserver reproducibility was substantial for surgeon experience level (< 5 years: 0.74 vs 5–10 years: 0.69 vs 10–20 years: 0.69 vs > 20 years: 0.70) and surgical subspecialty (orthopedic spine: 0.71 vs neurosurgery: 0.69 vs other: 0.68). Furthermore, the interobserver reliability was substantial for all surgical experience groups on assessment 1 (< 5 years: 0.67 vs 5–10 years: 0.62 vs 10–20 years: 0.61 vs > 20 years: 0.62), and only surgeons with > 20 years of experience did not have substantial reliability on assessment 2 (< 5 years: 0.62 vs 5–10 years: 0.61 vs 10–20 years: 0.61 vs > 20 years: 0.59). Orthopedic spine surgeons and neurosurgeons had substantial intraobserver reproducibility on both assessment 1 (0.64 vs 0.63) and assessment 2 (0.62 vs 0.63), while other surgeons had moderate reliability on assessment 1 (0.43) and fair reliability on assessment 2 (0.36). CONCLUSIONS The international reliability and reproducibility scores for the AO Spine Upper Cervical Injury Classification System demonstrated substantial intraobserver reproducibility and interobserver reliability regardless of surgical experience and spine subspecialty. These results support the global application of this classification system

Social Capital as an Instrument for Common Pool Resource Management: A Case Study of Irrigation Management in Sri Lanka

This paper investigates the effect of social capital between irrigation canal head-enders and tail-enders on their water allocation problem. In irrigation management, the water allocation problem between head-enders and tail-enders is one of the serious problems. Using unique natural and artefactual field experiment data as well as general household survey data collected by JICA, this study finds that social capital, especially trust toward their tail-enders, has a significantly positive effect on satisfaction with water usage among head-enders. Considering the fact that the incentive structure of irrigation water allocation for head-enders closely resembles that in the dictator and trust games, this finding also supports the validity of experimentally measured social capital. In addition, this study deals with the simultaneity bias between satisfaction level and experimentally measured social capital, and finds that OLS estimators are downward biased, which is consistent with the hypothesis that scarcity of resources enhances social capital

Revisiting suicide rate during wartime: Evidence from the Sri Lankan civil war.

After the seminal work of Durkheim (1897), many subsequent studies have revealed a decline in suicide rates during wartime. However, their main focus was inter-state wars and whether the same argument holds for civil conflicts within a country is an important unresolved issue in the modern world. Moreover, the findings of the previous studies are not conclusive due to unobserved confounding factors. This study investigated the relationship between civil war and suicide rate through a more rigorous statistical approach using the Sri Lankan civil war as a case study. For this purpose, we employed a linear regression model with district and year fixed effects to estimate a difference-in-difference in the suicide rate between the peacetime and wartime periods as well as the contested and non-contested districts. The results indicate that the suicide rate in the contested districts in the wartime was significantly lower than the baseline by 11.8-14.4 points (95% CI 6.46-17.22 and 7.21-21.54, respectively), which corresponds to a 43-52% decline. The robustness of the possible confounding factors was analyzed and not noted to have so much effect as to alter the interpretation of the results. This finding supports the Durkheimian theory, which places importance on social integration as a determinant of suicide, even for civil conflicts