byVictor Owusu Kwame Nkrumah University Science and .ppt
《byVictor Owusu Kwame Nkrumah University Science and .ppt》由会员分享,可在线阅读,更多相关《byVictor Owusu Kwame Nkrumah University Science and .ppt(19页珍藏版)》请在麦多课文档分享上搜索。
1、by Victor OwusuKwame Nkrumah University Science and Technology, Kumasi, Ghana Awudu AbdulaiUniversity of Kiel, Kiel, Germany Seini Yussif Abdul-RahmanKwame Nkrumah University Science and Technology, Kumasi, GhanaPaper Presentation at Impact Evaluation Conference. Cairo, Egypt. 29th March-2nd April 2
2、009,Impact of Nonfarm Employments on Food Security in Rural Ghana: A Propensity-Score Matching Approach,Outline of Presentation,Introduction and Problem Statement Research Questions Literature: Non-farm Employments and Food Security Hypotheses Relationship between Treatment and Outcome Variables Mat
3、ching Techniques Data Description Matching Results Results on Sensitivity Analysis Conclusions and Policy,Introduction and Problem Statement,Greatest challenge for sub-Saharan Africa is feeding ever-increasing population. Agriculture has not been a sufficient vehicle in addressing the household-leve
4、l malnutrition and food insecurity due to: Hostile agro ecological factors Low productivity Reducing hunger and food insecurity has been part of developmental agenda since the World Food Summits in 1996 and 2001. One possible pathways out of food insecurity in sub-Saharan Africa is the promotion and
5、 establishments of nonfarm employments (Barrett et al., 2001; Stamoulis and Zezza, 2003). Most rural communities in Africa derive 42% of income from nonfarm employments (Haggbade, Hazell and Reardon (2002).,Research questions,Does nonfarm employments reduce household food insecurity?To what extent d
6、oes nonfarm employment contributes to household food security?,Nonfarm Employment and Food Security,Improved access to nonfarm sources of income could lead to household welfare and food security (Holden et al., 2004; Winters et al., 2006). Most rural households in Ghana adopt various livelihood stra
7、tegies to safeguard food poverty (Ashong and Smith, 2001). Contribution of women to household food supplies and income in Ghana through nonfarm employments could complement agriculture (Canagarajah et al., 2001). What is not clear in the empirical literature is the direct causal effect of nonfarm em
8、ployment on household food security. Causal effects allow us to make inferences about the outcome that would have been observed for participants had they not participated in nonfarm employments. Main contribution of this paper is to examine the unobserved counterfactual outcome by employing matching
9、 techniques.,Hypotheses,Participation in non-farm employments by rural farmers increases household income.Household food security is influenced by participation in non-farm employments.,Relationship Between Treatment and Outcome Variables,Due to inadequate information on the counterfactual situation
10、, we resort to randomization by collecting non-experimental data (Blundell and Dias, 2000).Self-selection bias arises because the decision to participate or not to participate may be dependent on benefits of participation.Higher income effect could lead to household food security which also influenc
11、es non-farm employment participation.To account for the selection into treatment on observables, we use linear regression:,where,is household income for husbands (i=1), wives (i=2) and joint (i=3),If only husband participates, j=1, only wife participates, j=2,If joint participation by husband and wi
12、fe, j=3,is a treatment variable=1 if an individual participates and 0 otherwise,is the corresponding treatment effect,is a vector of confounding variables such as personal and household characteristics, and other location characteristics,is the error term with,.,is a vector of unknown parameters,For
13、 participation in non-farm employments, we can specify an index function for an observed variable H as,and error term, of outcome equation are correlated due to the influence, standard regression produces biased results.,of unobservable factors such that,Selection bias occurs if the error term, of t
14、reatment equation,When,To avoid this bias, we resort to matching techniques through covariate adjustments (Dehejia and Wahba, 2002).,Matching Techniques,Propensity-score (p-score) With experimental data, we employ the propensity score matching approach (Rosenbaum and Rubin, 1983). Given the p-score,
15、 the Average Treatment Effect (ATT) as noted by Becker and Ichino(2002) is estimated as,where,and,are two counterfactual outcomes of participation & non-participation,2. Implementation of the p-score Estimation of the p-score Choosing appropriate matching algorithm for the ATT Satisfying the common
16、support condition Assessing the matching quality Conditional Independence Assumption (CIA) Re-estimation of p-score of matched and unmatched participants (Sianesis Approach,2004) Sensitivity Analysis using the Bounding Approach (Rosenbaum,2002),Data Description,The cross-sectional data was collected
17、 in 2007 among 150 farm households with 300 married individuals in 10 rural communities in Savelugu-Nanton District of Northern Ghana. Treatment variables Dummy variable=1 if husband participates, 0 otherwise. Dummy variable=1 if wife participates, 0 otherwise. Dummy variable=1 if there is joint par
- 1.请仔细阅读文档,确保文档完整性,对于不预览、不比对内容而直接下载带来的问题本站不予受理。
- 2.下载的文档,不会出现我们的网址水印。
- 3、该文档所得收入(下载+内容+预览)归上传者、原创作者;如果您是本文档原作者,请点此认领!既往收益都归您。
本资源只提供5页预览,全部文档请下载后查看!喜欢就下载吧,查找使用更方便
2000 积分 0人已下载
下载 | 加入VIP,交流精品资源 |
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- BYVICTOROWUSUKWAMENKRUMAHUNIVERSITYSCIENCEANDPPT

链接地址:http://www.mydoc123.com/p-379218.html