2000年-世界发展银行全球_Socioeconomic_Inequalities_in_Child_Malnutrition_in_the_Developing_World_42页_1mb

Summary of "Socioeconomic Inequalities in Child Malnutrition in the Developing World"

Core Content

This working paper by Adam Wagstaff and Naoko Watanabe examines socioeconomic inequalities in child malnutrition across 20 developing countries. It highlights that while global progress has been made in reducing malnutrition, the issue remains concentrated among the poorest populations. The paper introduces the concentration index as a tool to measure these inequalities, using consumption quintiles to rank children and assess the distribution of malnutrition.

Main Findings

• Malnutrition is concentrated among the poor: Inequalities in malnutrition almost always disfavor the poor. The rate of malnutrition declines continuously with rising living standards.
• Inequalities are statistically significant: Inequalities in stunting and underweight are statistically significant in almost all countries, indicating a consistent pattern of disadvantage for the poor.
• Types of malnutrition differ in inequality levels: Inequalities in underweight tend to be larger than those in stunting, which in turn tend to be larger than those in wasting.
• Cross-country differences in inequality are not always significant: While some countries show notable differences in malnutrition inequality, most differences are not statistically significant.
• Some countries have more equal distributions: Egypt and Vietnam have the most equal distributions of malnutrition, whereas Nicaragua, Peru, and Morocco have highly unequal distributions.
• Performance varies between average and inequality: Some countries perform well on average malnutrition levels but poorly on inequality, and vice versa. Brazil, for example, has lower stunting rates than Bangladesh but higher inequality.
• Rank reversals using a summary index: Using a summary index that combines average malnutrition and inequality, countries like Egypt move up in rankings due to lower inequality, even if their average levels are not the best.
• Consumption inequality links to malnutrition inequality: The paper explores whether countries with high consumption inequality also have high malnutrition inequality, suggesting a possible correlation.
• Malnutrition dimensions are interrelated: Stunting, underweight, and wasting are linked, with children often suffering from multiple forms of malnutrition, but not always simultaneously.

Key Information

• Malnutrition indicators: The paper uses three main indicators—stunting, underweight, and wasting—to assess child malnutrition.
• Z-scores for malnutrition: These are used to standardize measurements of height-for-age, weight-for-age, and weight-for-height, with a -2Z-score indicating malnutrition.
• Concentration index: Defined as twice the area between the malnutrition concentration curve and the diagonal. It measures the degree of inequality in malnutrition across consumption quintiles.
• Methodological approach: The paper uses equivalent consumption to adjust for household size, and explores the use of equivalence scale elasticity to estimate this.
• Data sources: The study relies on Living Standards Measurement Study (LSMS) and Demographic and Health Surveys (DHS) data, with some regional coverage.
• Statistical tests: The paper employs t-tests and standard error estimators to assess the significance of differences in concentration indices across countries.

Methodology

• Concentration Curve: A graphical representation of malnutrition distribution across consumption quintiles.
• Concentration Index: A numerical measure derived from the concentration curve, used to quantify inequality.
• Standard Error Estimation: Adjusted for serial correlation in data, using a formula derived from Kakwani et al. [15].
• Equivalence Scale: Used to equate consumption across households of different sizes, with an elasticity of 0.5 used as a standard.

Conclusion

The paper emphasizes the importance of addressing both the average levels and the distribution of malnutrition in developing countries. It shows that while some countries have low levels of malnutrition and low inequality, others may excel in one area but perform poorly in the other. The introduction of a summary index that combines these two dimensions allows for a more nuanced assessment of national performance in tackling child malnutrition. The findings suggest that the current focus on population averages in international development goals may overlook significant disparities within countries, highlighting the need for a more equitable approach to malnutrition reduction.

Country Examples

• Egypt: Has the most pro-poor distribution for stunting and underweight.
• Vietnam: Leads in the most equal distribution for wasting.
• Nicaragua: Has the most unequal distribution for wasting.
• Peru: Has the most negative concentration indices for stunting and underweight.
• Brazil: Has lower stunting rates than Bangladesh but higher inequality.
• Bangladesh: Has lower inequality in stunting than Brazil and Côte d'Ivoire, though not statistically significant in the latter case.

Implications

• Policy focus: The paper advocates for a shift in policy focus from just reducing average malnutrition to also addressing inequalities.
• Data importance: It underscores the need for more comprehensive and comparable data to accurately measure and compare malnutrition across countries.
• Measurement consistency: The use of standardized metrics like Z-scores and concentration indices helps ensure consistency in analysis and interpretation.

References

• The paper references several studies and methodologies, including those by Wagstaff [13], Buhmann et al. [24], and Deaton and Zaidi [22], to support its analytical framework.