The extended skew-normal-based stochastic frontier model with a solution to ‘wrong skewness’ problem

Statistics ◽  
2021 ◽  
pp. 1-20
Author(s):  
Zheng Wei ◽  
Xiaonan Zhu ◽  
Tonghui Wang
2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Abebe Birara Dessie ◽  
Tadie Mirie Abate ◽  
Betelhem Tsedalu Adane ◽  
Tiru Tesfa ◽  
Shegaw Getu

Abstract Ethiopia is one of the east African countries which produce and exports various spices to other countries. Black cumin (Nigella sativa L.) is an important stiff annual flowering plant which mainly grows by producers for its seeds. An increasing demand of black cumin seed and oil in local, national and international market for medicinal, consumption and commercial purpose makes the best alternative crop for small holder farmers in Ethiopia. In spite of its importance, not much has been done to improve its production and productivity in Ethiopia. Therefore, this research was designed to examining efficiency variations and factors influencing technical inefficiency levels of producers on black cumin production in northwest Ethiopia. Primary data were collected using a semi-structured questionnaire administered on 188 black cumin producers selected using systematic random sampling technique. Moreover, various data analysis methods such as descriptive statistics and stochastic frontier model were used for analyzing the data. The empirical result obtained by applying maximum likelihood estimate of stochastic frontier model revealed that seed (p < 0.01) labor (p < 0.05), chemical (p < 0.01) and land (p < 0.05) were significant input variables in determining black cumin production. The mean technical efficiency level of black cumin producer was generally low, about 53.1%. The mean value of actual yield, potential yield and yield gap was 3.131, 5.832 and 2.701 quintals, respectively. Moreover, the result of stochastic frontier model together with the inefficiency parameters revealed that market price of black cumin (p < 0.01) and access of extension service (p < 0.1) were significant variables and positively influenced the efficiency levels of black cumin producers. Whereas age of producers (p < 0.05) and distance to farm plot (p < 0.01) negatively influenced the technical efficiency levels of black cumin producers. Therefore, the study recommends that adoption of latest agricultural technologies; development of institutions, agricultural extension services and infrastructure are advisable to improve the efficiency and commercial value of black cumin production.


2021 ◽  
Vol 49 (1) ◽  
pp. 136-163
Author(s):  
Ramon Christen ◽  
Nils C. Soguel

It is common practice to assign revenue to accomplish specific governmental tasks in general and to provide transport infrastructure in particular. However, neither the literature in public administration nor in public choice has reached a consensus about the effects that earmarking has on efficiency. Building on earlier public choice models, we argue that this mechanism prevents budget debates from occurring and reduces the incentives for ministers to monitor the colleagues whose budgets are financed by earmarked revenues. These latter tend to overuse public resources, thus increasing inefficiency. A stochastic frontier model fed with data from Swiss cantonal ministries of transport from 2000 to 2016 tests this hypothesis. The results reveal a negative effect of earmarking on efficiency. For every 1,000 additional Swiss francs per capita financed out of an earmarked fund, the input requirement increases by 5.4 percent on average.


2017 ◽  
Vol 33 (2) ◽  
pp. 967-982 ◽  
Author(s):  
Bernardo B. de Andrade ◽  
Geraldo S. Souza

Author(s):  
Sazcha Olivera ◽  
María del Pilar Fuerte-Celis ◽  
Bernardo Bolaños

The worldwide number of migrants has had a rapid increase during the last fifteen years. Despite the extensive research studies that elucidate the increase in migrants' recipient countries, we know little about the relationship between the climate factors and human mobility in the countries of origin. Hence, this study focuses on the effects of weather and the propensity of individuals to leave a territory by measuring the importance of rain precipitation or the lack of it in one of the critical food corridors of Central America, formed by El Salvador, Honduras, and Guatemala. To study the mobility process, we develop a stochastic frontier model; the main result shows a greater propensity to migrate when there is a significant drought event in the place of origin. Some other factors that motivate people to leave their homeland are the effect of other climate events measured through the control system (ENSO), homicide levels, economic performance, and exchange rate. The findings allow differentiating between drought and excess precipitation on a population and mobility to other territories. In addition, these results permit us to derive observable implications of the different effects of flooding and drought and create public policies of prevention, mitigation, and resilience.


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