文档介绍：!TECHNICAL GUIDE #3!
CLASSIFICATION AND REGRESSION TREES:
AN INTRODUCTION
Yisehac Yohannes
John Hoddinott
International Food Policy Research Institute
2033 K Street, .
Washington, . 20006 .
March, 1999
CONTENTS
1. Introduction ........................................................... 3-1
2. A CART Example: Indicators of Household Food Insecurity in Northern Mali ......... 3-2
3. Technical Details: Computing Requirements and Programming ..................... 3-6
4. Further Applications, Strengths, and Weaknesses of CART ....................... 3-9
1. INTRODUCTION1
Household food security (HFS) represents the guiding principle underlying many rural
development projects. It plays an important role in the targeting of projects, the selection of
appropriate interventions, and the monitoring and evaluation of projects. HFS is a multifaceted
concept that does not necessarily lend itself to measurement by single, discrete indicators.
Further, such indicators should reflect the behavior and livelihood conditions of target
populations—those that are most often, and more severely, affected by acute food insecurity
(Borton and Shoham 1991). These include the rural poor, women-headed households, asset-poor
pastoralists, the landless, recently resettled households, and households constrained by a high
dependency ratio.
The multifaceted nature of HFS implies that reliance on a single indicator is unlikely to
capture all dimensions of food security. Consequently, Borton and Shoham (1991) suggest 20
core indicators; Frankenberger (1992), and Seaman, Holt, and Allen (1993) each take between 20
and 30 indicators as the starting point; Riely (1993) and Downing (1993) both suggest more than
50 variables; while Currey (1978), one of the earliest practitioners in the field, started with 60
variables for his analysis of vulnerability in Bangladesh. The large number of potential
indicators presents development practitioners with several,