2008年-世界发展银行全球_World_Development_Indicators_2008___Poverty_Data_32页_3mb

2008 | World Development Indicators - Poverty Data Summary

Core Content

This document is a supplement to the World Development Indicators 2008 and provides updated global poverty estimates, including new purchasing power parities (PPPs) and revised international poverty lines. It outlines the methodology and data sources used to measure poverty at both the country and international levels, emphasizing the importance of PPPs in accurately reflecting the cost of living in different economies.

Main Points

New International Poverty Line

• The international poverty line has been updated from $1.08 a day (1993 prices) to $1.25 a day (2005 PPP prices).
• This change is based on new PPP data from the 2005 International Comparison Program and a larger set of national poverty lines from 1990 to 2005.
• The new line reflects the same real standard of living as the previous one but is adjusted for the current cost of living in developing countries.

Updated PPP Data

• PPPs are used to convert poverty lines from different currencies into a common unit of account.
• The 2005 PPPs indicate that price levels in developing countries are higher than previously estimated, meaning that earlier poverty lines were underestimated.
• The relationship between PPP and GDP per capita is negative, indicating that the purchasing power of a dollar is generally higher in poorer countries.

Global Poverty Estimates

• 1.4 billion people are estimated to live in extreme poverty based on the new $1.25 a day line.
• This represents more than one-quarter of the population in developing countries.
• The number of people living on less than $2 a day has remained relatively stable since 1981.

Regional and Country-Level Poverty

• The document provides country-level poverty measurements based on both national and international poverty lines.
• It includes regional poverty estimates and progress toward the Millennium Development Goals (MDGs), particularly in areas such as Sub-Saharan Africa and the Middle East and North Africa.
• The new data show a decline in poverty rates over the past 15 years, with an average annual reduction of 1 percentage point.

Methodology and Tools

• The PovcalNet tool is highlighted as a key method for calculating poverty estimates using the same data as the World Bank.
• It allows users to replicate global and regional poverty estimates, calculate poverty based on different groupings, and estimate poverty rates and gaps using various assumptions.

Key Information

Data Sources

• 675 household surveys from 115 developing countries (1979–2007) were used for poverty estimates.
• Surveys cover both income and consumption data, with a preference for consumption due to its better alignment with the standard of living.

Survey Quality and Limitations

• Nationally representative surveys are essential for accurate poverty measurement.
• Some surveys may underestimate or overestimate consumption due to differences in recall periods and data collection methods.
• Nonrepresentative surveys are excluded from international poverty rate calculations.

Challenges in Measurement

• Survey compliance varies by income level, potentially affecting the accuracy of poverty estimates.
• Urban bias is a concern in some countries, as many price surveys are conducted in urban areas.
• Adjustments are made using urban and rural poverty lines to reflect the actual cost of living in different regions.

Regional Poverty Trends

• Poverty rates have begun to fall globally, especially in East Asia.
• Sub-Saharan Africa and the Middle East and North Africa still have relatively high poverty rates.
• The proportion of the population covered by surveys has increased, reaching nearly 90% in recent years.

Figures and Tables

Figure 1

• Poverty lines rise with mean consumption above a critical level.
• The reference group includes 15 countries with average consumption below $60 a month.
• The new absolute poverty line is set at $38 a month or $1.25 a day.

Figure 2

• People represented by income or expenditure surveys.
• The population coverage rate has increased significantly over time.

Table 1

• Shows the number of surveys from low- and middle-income countries in each three-year interval (1980–2006).
• The number of surveys increased from 15 in 1980–82 to 118 in 2001–03, then slightly decreased due to data availability lags.

Conclusion

The new poverty estimates provide a more accurate reflection of the cost of living in developing countries and highlight the progress made in reducing extreme poverty over the past 15 years. While the international poverty line has been raised, the real standard of living remains the same. The document underscores the importance of comprehensive and representative survey data, PPPs, and country-specific price indices in producing reliable poverty estimates. It also emphasizes the need for continuous improvement in data collection and methodology to better understand and address global poverty.