Browsing by Subject "Average treatment effect"

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    Impact evaluation of improved rice varieties and farmer training on food security and technical efficiency in The Gambia
    (2016) Dibba, Lamin; Zeller, Manfred
    This dissertation aims to evaluate the impact of improved rice varieties and farmer training programs that have been introduced to boost local rice production in The Gambia. Rice is the main staple crop of The Gambia. The per capita consumption level of rice is estimated at 117 kg per annum, which is one of the highest in sub-Saharan Africa. The annual consumption of rice is estimated at 195, 811 metric tons, out of which only 51,137 metric tons are produced nationally. This huge deficit is met through imports, at an estimated cost of about US$ 50 million annually. As a result, the government is committed to attaining rice self-sufficiency. To achieve this objective, currents efforts have concentrated on the introduction of yield increasing improved rice varieties and farmer training programs. To evaluate how such improved rice varieties and farmer training programs are contributing towards the achievement of rice self-sufficiency in The Gambia is the main focus of this dissertation. To evaluate the impact of improved rice varieties and farmer training programs, this study has obtained a country-wide data from rice growing communities and households that were selected through a multi-stage stratified random sampling procedure. Data were obtained during 2006 and 2010 rice cropping seasons. The data collected were used to address three research topics: (1) How accessibility to seeds affects the potential adoption of an improved rice variety: The case of The New Rice for Africa (NERICA) in The Gambia, (2) The impact of New Rice for Africa (NERICA) adoption on household food security and health in The Gambia, and (3) The impact of agricultural training on technical efficiency of smallholder rice producers in The Gambia. These research topics are the main pillars of this dissertation. The aim of the first research topic was to assess the population adoption rate of NERICA and its determinants. The NERICA is a high yielding rice variety that was officially introduced in The Gambia in 2003. The introduction of NERICA was an attempt taken by the government to increase rice production and productivity in the country. This study focuses on two main constraints that limit the adoption of NERICA: awareness and access to its seeds. We used the treatment evaluation technique to address these constraints and estimate the true population adoption rate of NERICA in The Gambia. The results of our analysis show that the NERICA population adoption rate could have been 76% instead of the observed 66% sample estimate in 2010 provided that every rice farmer had been aware of NERICA’s existence before the 2010 rice growing season. However, further investigation finds that if all the rice farmers had been aware of and had access to NERICA seeds, adoption would have been 92%. The results further show that if awareness had not been a constraint, 16% of farmers would have failed to adopt NERICA due to lack of access to NERICA seeds. We found farmer contact with extension services and access to in-kind credit as significant determinants of access to and adoption of NERICA varieties. The policy implication of these findings is to increase farmer contact with extension and facilitate access to in-kind credit services like improved seeds to all the rice farming communities. This is likely to increase awareness and access to NERICA seeds, which can help to significantly close the population adoption gap of NERICA in The Gambia. Moreover, when efforts are made to make the entire rice farming population aware of the existence of NERICA varieties and also make the seeds of NERICA accessible to all rice farmers, then it will not be meaningful for future research to attempt to further estimate population adoption rate of NERICA in The Gambia. Under such circumstance, a more meaningful estimate of adoption is given by assessing the intensity of technology use among adopters. For the case of NERICA varieties, it will be more interesting to know the share of total rice area famers are allocating to NERICA varieties. This will give a better picture regarding the desirability of the NERICA technology by the target rice farming population. The second research topic attempts to identify improvements in household food security and health outcome indicators that can be attributed to NERICA adoption. We used food consumption scores (FCS) and sick days per capita among farm households’ members as outcome indicators of food security and health, respectively. Since NERICA adoption is a decision made by rice farmers, we assume that this selection decision is partly based on unobservable factors, for example, farmers’ attitude towards work. Therefore, we used the instrumental variable approach to identify causal effects of NERICA adoption on food security and health. The results of our analysis show significant differences in some key socio-economic and demographic characteristics between NERICA adopters and non-adopters. These adopting households. However, the results of our analysis have shown no significant impact of NERICA adoption on health. This could be attributed to the fact that we used information on all household members to create number of sick days per capita. Given the limited scope of the survey data regarding health, more precise indicators of health, such as detailed individual recall data on specific diseases, anthropometric data, or other health indicators were not available. Number of sick days per capita is a highly noisy indicator which tend to be negatively correlated with household size. When one individual respondent reports on the health status of all households members, it can lead to under estimation if the household is large. For this reason, we recommend that future studies that intend to identify the impact of NERICA adoption on health should focus on individual recall data, which may be a better outcome indicator. Finally, the third research topic aims to identify improvements in technical efficiency of smallholder rice farmers that can be attributed to agricultural rice farmer training programs introduced in The Gambia to increase rice production and productivity. Technical efficiency is a measure of how the use of best rice farming practices affects the total yield of rice farmers. Technical efficiency is achieved when it is not possible to increase output without increasing inputs. Due to technical inefficiencies, there is a huge gap between actual and potential yields of rice farmers in sub-Saharan Africa. For instance, the rice yield of upland farmers, in sub-Saharan Africa, is estimated at 1 t/ha whereas the yields at research stations ranges between 2.5 to 5 t/ha. This yield gap is mainly attributed to inappropriate farming practices and lack of farmers’ access to modern inputs that influence efficiency in farmers’ fields. As a result, this study assesses how the introduction of best agricultural rice farming practices, through agricultural training programs, affects the technical efficiency of smallholder farmers in The Gambia. In the first stage, we use Data Envelopment Analysis (DEA) technique to estimate technical efficiency scores for each sampled household and used Tobit regression to identify factors influencing technical efficiency. In the second stage, we employ propensity score matching to assess program impact on participants using technical efficiency scores as our outcome indicator. The results of the analysis indicate that agricultural training significantly increases technical efficiency of smallholder rice farmers by 10 percent. This translates to rice yield increase of 260 kg/ha, which results in net social and private benefits per annum of US$ 43700 for 900 rice farming households and 30 extension agents, and US$ 53 per household, respectively. Our analysis of investment on agricultural training yields a Net Present Value (NPV) of US$ 195816, a Benefit Cost Ratio (BCR) of 5.3 and an Internal Rate of Return (IRR) of 99%. These results justify increased investment on agricultural training programs to boost rice production and productivity. Further analysis to identify determinants of technical efficiency show farmer’s contact with extension workers and a farmer’s association membership as significant factors influencing technical efficiency. The significance of farmer’s contact with extension and association membership in determining technical efficiency indicates that extension contact and association membership could be important impact pathways to improve technical efficiency among smallholder farmers. The policy implication of these findings is to encourage rice farmers, through agricultural extension services, to be members of rice farmers associations and motivate them to meet regularly to exchange ideas and information about new developments within and outside their rice farming communities. Moreover, we define agricultural training as participation in at least one rice farmer training program. Since some training programs are likely to be more effective than others, defining participation as receipt of at least one training on rice cultivation practices is likely to underestimate the impact of highly effective training programs. Consequently, we recommend that future studies that intend to assess the impact of agricultural training on technical efficiency should identify specific training programs and assess their impact on technical efficiency separately.