An Application of Small Area Estimation
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Public Disclosure Authorized POVERTY AND INEQUALITY ON THE Public Disclosure Authorized MAP IN THE GAMBIA An Application of Small Area Estimation Public Disclosure Authorized Public Disclosure Authorized POVERTY AND INEQUALITY ON THE MAP IN THE GAMBIA November 2018 1 | Page This publication is prepared with the support of the Country Management Unit West Africa Poverty Monitoring Code (WAPMC - P164474). Extracts may be published if source is duly acknowledged. Copyright © 2018 by The Gambia Bureau of Statistics The Statistician General P. O. Box 3504, Serekunda, The Gambia Tel. +220 4377847 Fax: +220 4377848 Authors Rose Mungai Minh Cong Nguyen Tejesh Pradhan Supervisor Andrew Dabalen Graphic presentation of the data Minh Cong Nguyen Editor Lauri Scherer Table of Contents Acknowledgments ............................................................................................................................... 4 Abstract ............................................................................................................................................... 5 Abbreviations ...................................................................................................................................... 6 1. Introduction ............................................................................................................................. 7 1.1 The Gambia country context ...................................................................................................... 8 2. Overview of the Methodology ............................................................................................... 9 3. The Data ................................................................................................................................. 12 3.1. Integrated Household Survey 2015/16 .................................................................................... 12 3.2. Population census .................................................................................................................... 13 4. Modeling for Monetary Poverty .......................................................................................... 14 5. Model Selection ..................................................................................................................... 18 5.1 Default stepwise ....................................................................................................................... 19 5.2 Stepwise AIC ............................................................................................................................ 19 5.3 Post-lasso .................................................................................................................................. 19 5.4 Random forest ........................................................................................................................... 20 6. Poverty Mapping Results ...................................................................................................... 30 7. Conclusion .............................................................................................................................. 49 References ......................................................................................................................................... 50 List of Appendixes Appendix A: The Gambia: Administrative Boundaries ..................................................................... 53 Appendix B: Region Alpha Model Estimates .................................................................................... 54 Table B1: Banjul (Alpha Model, LGA 1) ....................................................................................... 54 Table B2: Kanifing (Alpha Model, LGA 2) ................................................................................... 54 Table B3: Brikama (Alpha Model, LGA 3) ................................................................................... 54 Table B4: Mansakonko (Alpha Model, LGA 4) ............................................................................. 54 Table B5: Kerewan (Alpha Model, LGA 5) ................................................................................... 55 Table B6: Kuntaur (Alpha Model, LGA 6) .................................................................................... 55 Table B7: Janjangbureh (Alpha Model, LGA 7) ............................................................................ 55 Table B8: Basse (Alpha Model, LGA 8) ........................................................................................ 56 1 | Page Appendix C: Poverty Measures .......................................................................................................... 57 Appendix D: Census Poverty Measures by Administrative Units ..................................................... 59 Table D1: Poverty Measures by Local Government Area and District .......................................... 59 Table D2: Poverty Measures by Ward ........................................................................................... 61 Appendix E: Census Nonmonetary Indicators by Administrative Units ........................................... 66 Table E1: Population Characteristics by Local Government Area and District ............................. 66 Table E2: Household Nonmonetary Measures by Local Government Area and District .............. 66 Appendix F: Census Population Poverty Profiles by Administrative Units ...................................... 72 Table F1: Population Poverty Profiles by Local Government Area and District ........................... 72 Table F2: Household Poverty Profiles by Local Government Area and District ........................... 74 List of Boxes Box 1: Step-by-Step Summary of the Modeling Approach ............................................................... 11 List of Figures Figure 1: Households, Population, Household Size, and Total Fertility Rate by Census Year ......... 14 Figure 2: Distributions with Actual and Imputed Testing Sample ..................................................... 29 List of Tables Table 1: Geographical Distribution between the Census (2013) and Survey (2015/16).................... 16 Table 2: Comparison of Household Characteristics between Census (2013) and Survey (2015/16), Weighted Average ........................................................................................................................ 17 Table 3: Model Estimates Based on IHS 2015/16—Banjul (Beta Model, LGA 1) ........................... 21 Table 4: Model Estimates Based on IHS 2015/16—Kanifing (Beta Model, LGA 2)........................ 22 Table 5: Model Estimates Based on IHS 2015/16—Brikama (Beta Model, LGA 3) ........................ 23 Table 6: Model Estimates Based on IHS 2015/16—Mansakonko (Beta Model, LGA 4) ................. 24 Table 7: Model Estimates Based on IHS 2015/16—Kerewan (Beta Model, LGA 5) ....................... 25 Table 8: Model Estimates Based on IHS 2015/16—Kuntaur (Beta Model, LGA 6) ......................... 26 Table 9: Model Estimates Based on IHS 2015/16—Janjangbureh (Beta Model, LGA 7) ................ 27 Table 10: Model Estimates Based on IHS 2015/16—Basse (Beta Model, LGA 8) .......................... 28 Table 11: Poverty Estimates from Survey (Observed) and the Census (Small Area Estimation) ..... 30 Table 12: Census Small Area Estimation of Poverty and Gini at the National and Local Government Area .............................................................................................................................................. 30 2 | Page Table 13: Census Small Area Estimation of Poverty and Gini at the District Level ......................... 34 Table 14: Census Small Area Estimation of Poverty and Gini at the Ward Level ............................ 39 List of Maps Map 1: Census Small Area Estimation of Poverty at the Local Government Area ........................... 31 Map 2: Census Small Area Estimation of Number of Poor at the Local Government Area.............. 32 Map 3: Census Small Area Estimation of Poverty at the District Level ............................................ 36 Map 4: Census Small Area Estimation of Number of Poor at the District Level .............................. 37 Map 5: Census Small Area Estimation of Gini at the District Level ................................................. 38 Map 6: Census Small Area Estimation of Poverty at the Ward Level ............................................... 43 Map 7: Census Small Area Estimation of Poverty at the Ward Level (Zoom in at Banjul and Kanifing) ................................................................................................................................ 44 Map 8: Census Small Area Estimation of Number of Poor at the Ward Level ................................. 45 Map 9: Census Small Area Estimation of Number of Poor at the Ward Level (Zoom in at Banjul and Kanifing) .......................................................................................................................... 46 Map 10: Census Small Area Estimation of Gini at the Ward Level .................................................. 47 Map 11: Census Small Area Estimation of Gini at the Ward Level (Zoom in at Banjul and Kanifing) ................................................................................................................................................ 48 3 | Page Acknowledgments This note was prepared by a core team of Rose Mungai (Senior Economist/Statistician,