2016年-世界发展银行全球_Constructing_Robust_Poverty_Trends_in_the_Islamic_Republic_of_Iran_2008-14_27页_1mb

Summary of "Constructing Robust Poverty Trends in the Islamic Republic of Iran"

Core Content

This working paper analyzes poverty and inequality trends in the Islamic Republic of Iran from 2008 to 2014 using internationally comparable measures. The authors construct and test the robustness of poverty trends using international poverty lines expressed in USD at 2011 purchasing power parity (PPP). They aim to provide a consistent and reliable measure of welfare over time, which is essential for understanding the impact of economic shocks and policy interventions.

Main Findings

• Three distinct periods of welfare in Iran are identified:

  • Increase in poverty and inequality between 2008 and 2009.
  • Decline in poverty and inequality between 2009 and 2012.
  • Gradual deterioration of both indicators after 2012.

• The results are robust to different choices of welfare aggregates, inclusion or exclusion of components, and spatial adjustments for regional price variations.

• The Household Expenditure and Income Survey (HEIS) is used as the primary data source, with unit record data available from 1984 onward. The survey is nationally representative and conducted annually since 1963 in rural areas and 1968 in urban areas.

Key Methodological Approaches

1. Welfare Aggregate Construction

• The welfare aggregate is based on expenditure and includes:
  • Food (purchases or estimated value of all food items, excluding tobacco).
  • Non-food (tobacco, miscellaneous, hotel, leisure, communication, transport, furniture, housing, clothing, rent, education, and health insurance).
• Health and durable expenditures are excluded due to data limitations and ambiguity in their contribution to welfare.
• Education expenditures are included as they are closely associated with utility and welfare.
• Health insurance is included because it is clearly linked to preventive care and thus welfare.

2. Price Adjustments

• Inflation data are sourced from the Statistical Centre of Iran (SCI) and the Central Bank of Iran (CBI), with SCI data used for its broader coverage of rural and urban areas.
• Inter-temporal deflation is applied to adjust for inflation within and across years using the SCI CPI.
• Spatial deflation is conducted to account for regional price differences:
  • Food deflator is based on the Paashe index using unit prices of food items.
  • Rent deflator is estimated using a hedonic regression model based on actual and estimated rents.
• The welfare aggregate and its components are normalized after spatial deflation to ensure the mean remains consistent.

3. Robustness Checks

• The poverty and inequality estimates are tested across different welfare aggregates and price adjustments.
• The findings are consistent regardless of the method used, indicating the reliability of the constructed poverty trends.
• Income data are also used for a brief robustness check, showing similar trends to those derived from expenditure data.

Important Considerations

• Poverty rates are sensitive to the choice of poverty line, but the paper uses international lines to avoid the arbitrariness of local currency lines.
• Data limitations are acknowledged, particularly the lack of detailed information on durable and health expenditures.
• Seasonality and survey timing are important factors in poverty measurement, as they can influence the recall period and thus the accuracy of expenditure data.

Conclusion

The paper concludes that constructing a consistent and spatially adjusted welfare aggregate is crucial for understanding poverty and inequality trends in Iran, especially in the context of economic shocks and policy changes. It provides a methodological framework for future poverty measurement and highlights the importance of data quality and consistency in poverty analysis. The findings may support the development of an official poverty measurement system in Iran.

Key Information

• Period analyzed: 2008–2014.
• Data source: HEIS, conducted annually since 1963 in rural areas and 1968 in urban areas.
• Poverty lines used: International poverty lines at USD 2011 PPP (1.90 USD).
• Methodological focus: Expenditure-based welfare aggregate, spatial and inter-temporal deflation, robustness checks.
• Trends identified:
  • Poverty increased from 2008 to 2009.
  • Poverty decreased from 2009 to 2012.
  • Poverty gradually worsened after 2012.
• Inequality (Gini coefficient): Declined from 42% to 37.4% between 2009 and 2013, but showed signs of deterioration post-2012.

Structure of the Paper

1. Introduction: Sets the context and highlights the need for consistent poverty measurement.
2. Methodological issues in poverty measurement: Discusses the choice between income and consumption as welfare indicators and the importance of consistent measurement across time.
3. Expenditure-based welfare aggregate and its components: Explains the construction of the aggregate and the components included or excluded.
4. Adjustments to the welfare aggregate: Covers inflation data, inter-temporal and spatial deflation methods.
5. Robustness checks of expenditure-based poverty and inequality estimates: Tests the reliability of the constructed trends.
6. Robustness check using income data: Briefly compares income-based and expenditure-based poverty trends.
7. Conclusion: Summarizes the findings and their implications for policy and future research.