Papers by Victor Afari-Sefa
Journal of Development and Agricultural Economics
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The role of technology - its economics and factors that influence technological choice decisions ... more The role of technology - its economics and factors that influence technological choice decisions have
been a concern in development policy. Logit and probit functional forms have been largely used in
modelling technology choice (adoption). We employed two other functional forms; loglog and cloglog,
applied to adoption of Fairtrade and organic cocoa producers in the Eastern Region of Ghana. Using
fractional regression modelling, we demonstrate the need to explore alternative functional forms other
than logit and probit, in binary choice related problems. Interestingly, the battery of tests employed
rejected the logit and probit functional forms. Alternative assessment criteria such as size, statistical
significance of parameters and differences in parameter estimates produced more interesting results.
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Traditional African vegetables are receiving more attention for their significant contribution to... more Traditional African vegetables are receiving more attention for their significant contribution to food and nutrition security and enhanced livelihoods of smallholders. Although demand is increasing for these nutrients-dense crops, the production of traditional vegetables in Tanzania remains low. Technical
innovations can reduce yield gaps and increase the productivity of traditional vegetable crops. This paper measures the technical efficiency of farm households that produce traditional vegetables in Tanzania using a Cobb-Douglas stochastic frontier production function. This study reports data from a primary survey of 181 households that cultivated traditional vegetables in five regions (Arusha, Tanga, Morogoro, Dodoma and Dar es Salaam) of Tanzania. The results show that overall mean technical efficiency is 67%. It indicates that if the average farmer of the sample could achieve the technical efficiency level of most efficient counterpart, then average farmers of the sample could increase their output by 27% with better use of available production resources given the current state of technology.
Farmers were observed to be more technically efficient in the Arusha region than in the other study regions. Possible reasons for the observed regional difference include agroclimatic variability, access to extension services, and infrastructure facilities. A linear relationship exists between farm size and
technical efficiency. The study concludes that strengthening farmer associations to encourage knowledge sharing and enhancing the existing cluster approach to farming may help to improve technical efficiency.
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International Food and Agribusiness Management Association
Several studies have shown that traditional vegetables have high market potential and contribute ... more Several studies have shown that traditional vegetables have high market potential and contribute substantially to household incomes and nutrition. Until recently however, the scientific and donor community often give less attention to research on traditional vegetable crop value chains. The resurgence of traditional vegetables’ importance in human nutrition is accompanied by a need to understand the interactions among various actors in their value chain to determine ways to add value to produce and improve marketing efficiency. Based on a multistage cross-sectional survey of 240 respondents in Malawi and Mozambique, this study employed participatory evaluation and market research to identify potential outlets and target crops, and define value chain processes, including choice of market outlets and mode of farmer-buyer linkages. Traditional vegetable sales contributed about 35% and 30% of smallholders’ income in Malawi and Mozambique respectively. Linkages between value chain actors...
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Biological Agriculture & Horticulture, 2012
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Agroforestry Systems, 2014
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Recent years have seen increasing political interest and growing public health awareness and advo... more Recent years have seen increasing political interest and growing public health awareness and advocacy for
diversifying diets into highly nutritious traditional vegetables, fruits and other nutrition-sensitive crops as a
more viable approach to mitigate the growing scourge of malnutrition due to unhealthy and imbalanced
diets. These foods contribute essential micronutrients, vitamins, antioxidants, and other health-related
phytochemicals to staple-based diets and their consumption is crucial for the attainment of several
Millennium Development Goals. Despite their nutritional benefits and the high farm gate values per
unit of land, the production and marketing of traditional vegetables from Tanzania and other countries
in sub-Saharan Africa are constrained by factors such as poor quality seeds, lack of appropriate market
information and support systems, and lack of consumer awareness of their nutritional importance. This
paper investigates the determinants and pathways for smallholder participation in traditional African
vegetable production and identifies entry points for farmers to increase traditional vegetable production by
linking nutritional awareness and promotion with potential high value markets. A primary survey of 181
traditional vegetable growers from five regions of Tanzania indicates that perceptions about the nutritional
value of traditional African vegetables are a main driver of household production decisions in the sector.
The results of this study provide evidence that farmers tend to grow more African traditional vegetables as
compared to other crops based on their increased level of perception towards nutritional value of traditional
vegetables along with other factors such as their market value, timely availability of quality certified seeds,
willingness to invest in labour, required training for women and better access to credits. Farmsize negatively
affects growing traditional vegetables, implying that on a comparative basis, smallholders tend to grow
more traditional vegetables than larger-farm operators. Thus, more attention should be given to reducing
production and its associated transaction costs by ensuring timely access to quality certified seeds, ensuring
optimal use of inputs and increasing labour productivity, particularly for smallholders.
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Conference Presentations by Victor Afari-Sefa
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Papers by Victor Afari-Sefa
been a concern in development policy. Logit and probit functional forms have been largely used in
modelling technology choice (adoption). We employed two other functional forms; loglog and cloglog,
applied to adoption of Fairtrade and organic cocoa producers in the Eastern Region of Ghana. Using
fractional regression modelling, we demonstrate the need to explore alternative functional forms other
than logit and probit, in binary choice related problems. Interestingly, the battery of tests employed
rejected the logit and probit functional forms. Alternative assessment criteria such as size, statistical
significance of parameters and differences in parameter estimates produced more interesting results.
innovations can reduce yield gaps and increase the productivity of traditional vegetable crops. This paper measures the technical efficiency of farm households that produce traditional vegetables in Tanzania using a Cobb-Douglas stochastic frontier production function. This study reports data from a primary survey of 181 households that cultivated traditional vegetables in five regions (Arusha, Tanga, Morogoro, Dodoma and Dar es Salaam) of Tanzania. The results show that overall mean technical efficiency is 67%. It indicates that if the average farmer of the sample could achieve the technical efficiency level of most efficient counterpart, then average farmers of the sample could increase their output by 27% with better use of available production resources given the current state of technology.
Farmers were observed to be more technically efficient in the Arusha region than in the other study regions. Possible reasons for the observed regional difference include agroclimatic variability, access to extension services, and infrastructure facilities. A linear relationship exists between farm size and
technical efficiency. The study concludes that strengthening farmer associations to encourage knowledge sharing and enhancing the existing cluster approach to farming may help to improve technical efficiency.
diversifying diets into highly nutritious traditional vegetables, fruits and other nutrition-sensitive crops as a
more viable approach to mitigate the growing scourge of malnutrition due to unhealthy and imbalanced
diets. These foods contribute essential micronutrients, vitamins, antioxidants, and other health-related
phytochemicals to staple-based diets and their consumption is crucial for the attainment of several
Millennium Development Goals. Despite their nutritional benefits and the high farm gate values per
unit of land, the production and marketing of traditional vegetables from Tanzania and other countries
in sub-Saharan Africa are constrained by factors such as poor quality seeds, lack of appropriate market
information and support systems, and lack of consumer awareness of their nutritional importance. This
paper investigates the determinants and pathways for smallholder participation in traditional African
vegetable production and identifies entry points for farmers to increase traditional vegetable production by
linking nutritional awareness and promotion with potential high value markets. A primary survey of 181
traditional vegetable growers from five regions of Tanzania indicates that perceptions about the nutritional
value of traditional African vegetables are a main driver of household production decisions in the sector.
The results of this study provide evidence that farmers tend to grow more African traditional vegetables as
compared to other crops based on their increased level of perception towards nutritional value of traditional
vegetables along with other factors such as their market value, timely availability of quality certified seeds,
willingness to invest in labour, required training for women and better access to credits. Farmsize negatively
affects growing traditional vegetables, implying that on a comparative basis, smallholders tend to grow
more traditional vegetables than larger-farm operators. Thus, more attention should be given to reducing
production and its associated transaction costs by ensuring timely access to quality certified seeds, ensuring
optimal use of inputs and increasing labour productivity, particularly for smallholders.
Conference Presentations by Victor Afari-Sefa
been a concern in development policy. Logit and probit functional forms have been largely used in
modelling technology choice (adoption). We employed two other functional forms; loglog and cloglog,
applied to adoption of Fairtrade and organic cocoa producers in the Eastern Region of Ghana. Using
fractional regression modelling, we demonstrate the need to explore alternative functional forms other
than logit and probit, in binary choice related problems. Interestingly, the battery of tests employed
rejected the logit and probit functional forms. Alternative assessment criteria such as size, statistical
significance of parameters and differences in parameter estimates produced more interesting results.
innovations can reduce yield gaps and increase the productivity of traditional vegetable crops. This paper measures the technical efficiency of farm households that produce traditional vegetables in Tanzania using a Cobb-Douglas stochastic frontier production function. This study reports data from a primary survey of 181 households that cultivated traditional vegetables in five regions (Arusha, Tanga, Morogoro, Dodoma and Dar es Salaam) of Tanzania. The results show that overall mean technical efficiency is 67%. It indicates that if the average farmer of the sample could achieve the technical efficiency level of most efficient counterpart, then average farmers of the sample could increase their output by 27% with better use of available production resources given the current state of technology.
Farmers were observed to be more technically efficient in the Arusha region than in the other study regions. Possible reasons for the observed regional difference include agroclimatic variability, access to extension services, and infrastructure facilities. A linear relationship exists between farm size and
technical efficiency. The study concludes that strengthening farmer associations to encourage knowledge sharing and enhancing the existing cluster approach to farming may help to improve technical efficiency.
diversifying diets into highly nutritious traditional vegetables, fruits and other nutrition-sensitive crops as a
more viable approach to mitigate the growing scourge of malnutrition due to unhealthy and imbalanced
diets. These foods contribute essential micronutrients, vitamins, antioxidants, and other health-related
phytochemicals to staple-based diets and their consumption is crucial for the attainment of several
Millennium Development Goals. Despite their nutritional benefits and the high farm gate values per
unit of land, the production and marketing of traditional vegetables from Tanzania and other countries
in sub-Saharan Africa are constrained by factors such as poor quality seeds, lack of appropriate market
information and support systems, and lack of consumer awareness of their nutritional importance. This
paper investigates the determinants and pathways for smallholder participation in traditional African
vegetable production and identifies entry points for farmers to increase traditional vegetable production by
linking nutritional awareness and promotion with potential high value markets. A primary survey of 181
traditional vegetable growers from five regions of Tanzania indicates that perceptions about the nutritional
value of traditional African vegetables are a main driver of household production decisions in the sector.
The results of this study provide evidence that farmers tend to grow more African traditional vegetables as
compared to other crops based on their increased level of perception towards nutritional value of traditional
vegetables along with other factors such as their market value, timely availability of quality certified seeds,
willingness to invest in labour, required training for women and better access to credits. Farmsize negatively
affects growing traditional vegetables, implying that on a comparative basis, smallholders tend to grow
more traditional vegetables than larger-farm operators. Thus, more attention should be given to reducing
production and its associated transaction costs by ensuring timely access to quality certified seeds, ensuring
optimal use of inputs and increasing labour productivity, particularly for smallholders.