2017年-世界发展银行全球_Societal_Poverty___A_Relative_and_Relevant_Measure_48页_999kb

Summary of "Societal Poverty: A Relative and Relevant Measure"

Core Content

This paper introduces a new global poverty measure called the Societal Poverty Line (SPL), which is designed to reflect the relative nature of poverty as assessed by individual countries. Unlike the traditional fixed-value international poverty line (e.g., $1.90 per day), the SPL is a relative measure that adjusts based on a country's median income or consumption, making it more aligned with national definitions of poverty.

Main Points

• Relative vs Absolute Poverty Lines:
  Absolute poverty lines are fixed in value, while relative poverty lines are adjusted according to a country's overall income level. The SPL incorporates both elements by having a fixed intercept and a relative gradient, making it a hybrid measure.

• Definition of the SPL:
  The proposed SPL has an intercept of $1 per day (in 2011 PPP terms) and a relative gradient of 50 percent of the median national income or consumption. This design allows the poverty line to rise as a country becomes wealthier, reflecting the evolving cost of basic needs.

• Rationale for SPL:
  The SPL is intended to better represent how different countries define poverty, especially as their economies grow and the cost of basic needs increases. It also addresses the concern that the fixed international poverty line may no longer be socially relevant in richer nations.

• Data Sources:
  The SPL is derived from 699 harmonized national poverty lines, covering 107 countries. The data are sourced from the Jolliffe-Prydz database, which improves upon previous datasets by offering better temporal and geographic coverage.

• Methodology:
  The paper uses regression analysis to estimate the SPL parameters. It compares the fit of poverty lines using median versus mean consumption and finds that the median provides a more accurate and stable representation of national poverty lines.

• Results:
  The regression results show that the intercept is approximately $1 per day and the slope is 50 percent of the median. These estimates are consistent across both the full sample and the 2011 subsample, indicating that the SPL is a stable and relevant measure.

Key Information

• Global Poverty Trends:
  Since 1990, the societal poverty rate has declined steadily, though at a slower pace than absolute extreme poverty.

• Comparisons with Existing Lines:

  • The international poverty line (e.g., $1.90) is fixed and absolute.
  • The Atkinson-Bourguignon line sets the intercept at $1 and the slope at 37 percent of mean expenditure.
  • The Ravallion-Chen line sets the intercept at $0.625 and the slope at 50 percent of mean consumption.
  • The SPL has an intercept of $1 and a slope of 50 percent of the median consumption or income, which is considered more robust and reflective of national assessments.

• Temporal and Geographic Coverage:
  The full sample includes 699 poverty lines from 1984 to 2013, while the circa-2011 sample includes 104 lines from countries with the most recent poverty lines (after 2000). The latter allows for a more recent analysis and better inflation data alignment.

• Implications:
  The SPL offers a more relevant and nuanced measure of poverty that reflects national perspectives on wellbeing. It is particularly useful for comparative analysis across countries and for understanding how poverty is redefined as economies grow.

Conclusion

The SPL is a more accurate and socially relevant measure of global poverty than the fixed international poverty line. It combines a fixed intercept with a relative gradient, ensuring that it adapts to changes in a country's economic development. This approach better reflects the dynamic nature of poverty and aligns with the relative poverty standards used in many high-income countries. The paper emphasizes that the SPL is not only a better representation of national poverty assessments but also provides a more consistent and comparable framework for global poverty analysis.

Structure of the Paper

• I. Introduction:

  • Introduces the concept of relative poverty and the need for a more relevant global measure.
  • Explains how national poverty lines reflect changes in basic needs as countries develop.

• II. Global Poverty, Concepts and Data:

  • Reviews existing global poverty lines, including the absolute international poverty line and relative lines.
  • Describes the Jolliffe-Prydz database and the methodology used to compile and harmonize national poverty lines.

• III. Setting and Assessing the Societal Poverty Line:

  • Details the regression analysis used to determine the SPL parameters.
  • Compares the fit of poverty lines using median versus mean consumption.
  • Highlights the stability of the SPL relationship over time.

• IV. Geographic and Temporal Profiles of Societal Poverty:

  • Analyzes how societal poverty varies across countries and over time.
  • Shows that the SPL is consistent with national assessments and better reflects the changing cost of basic needs.

Figures and Tables

• Figure 1:

  • Summarizes different global poverty line proposals and their parameters.

• Figure 2:

  • Plots the national poverty lines against median consumption or income, showing a strong positive correlation.

• Table 2:

  • Presents regression results for the full sample and the circa-2011 subsample, highlighting the intercept and slope estimates.