AAMP Training Materials

1. AAMP Training Materials Module 3.3: Household Impact of Staple Food Price Changes Nicholas Minot (IFPRI) n.minot@cgiar.org

2. Why are we interested in the household-level impact of food price changes? • Food policies  food prices  well-being of people • It is not enough to know the total costs and total benefits of alternative food policies • Policy-makers are also interested in equity • So they want to know impact of food policy on poor households, on vulnerable groups, on poverty rate, on inequality • Policy-makers also take into account political economy • So they want to know impact of food policy on households in rural vs urban areas, different regions, different occupations, different ethnic groups, different farm-size categories, etc. • Thus, need to estimate impact of food price changes on different types of households

3. Objectives • Understand how staple food price changes affect households • Measure the welfare impact of price changes • Calculate the net benefit ratio (NBR) • Use NBR to understand the welfare impact of price changes • Identify the characteristics of net buyers and sellers in sub-Saharan Africa

4. How do price changes affect households? • Higher prices of consumer goods hurt households • Higher prices of crops benefit farm households • But: • What about households that are mostly self-sufficient? • How about households that buy and sell the same good? • And how much do they gain or lose? • Economics helps us measure the size of the benefit or loss in income

5. How price increases affect households Case of consumers • Blue area represents cost to consumers • Blue + green area is approximation and easier to measure • Welfare effect ≅ negative Δ price x quantity consumed • Amount of additional income that would allow you to consume as much as before the price increase Price demand Quantity

6. How price increases affect households Case of producers • Blue + green area represents benefit to producers • Green area is approximate and easier to measure • Welfare effect ≅ positive Δ price x quantity produced • Amount of additional income that producer would get if there was no change in output Price supply Quantity

7. How price increases affect households Y=income, P=price, Qd=demand, Qs=supply • Δ y ≅ ΔP Qs – ΔP Qd • = ΔP (Qs – Qd) • = ΔP (PQs - PQd) P • Δy ≅ ΔP(PQs - PQd) y P y Price Quantity

8. What is the net benefit ratio (NBR)? • The percentage change in real income • is approximately equal to • the percentage change in price multiplied by • the value of net sales of a crop divided by income. • ΔY≅ ΔP (PQs - PQd) • Y P Y • Net benefit ratio (NBR) The NBR is usually calculated for a crop (e.g. maize) or a crop category (e.g. cereals).

9. Using the NBR to understand the welfare impact of price changes

10. Using the NBR to understand the welfare impact of price changes

11. What are the characteristics of net buyers and net sellers? * Net sellers and net buyers together are 12% Source: Jayne et al, 2005, Tefera and Seyoum, 2008, Dorosh and Minten, 2006.

12. What are the characteristics of net buyers and net sellers?

13. What are the characteristics of net buyers and net sellers? Generally, NBR rises with income, that is, net sellers are richer than net buyers Source: Tefara and Seyoum, 2008

14. Exercise 1 • If a farmer produces $800 of maize and consumes $300 and household income is $1000, what is the maize NBR for this household? • If maize prices fall 20%, what is the approximate percentage fall in this farmer’s income? • Suppose a farmer produces cassava for own consumption, but does not buy or sell it. What is the cassava NBR? • If cassava prices rise 20%, what is the change in income for this household?

15. Exercise 2 • Open the file: • Module 3.4 – household impact of food price changes.xls • Calculate household expenditure as per capita expenditure x household size • Calculate the NBR for maize for each household as (sales – purchases)/household expenditure • Calculate the % change in income as the NBR x the percentage increase in maize price (cell C4) • Calculate the new expenditure per capita as original per capita expenditure x (1+% change in income)

16. Exercise 2 (continued) • In column L, calculate a dummy variable indicating households that were poor before the price change using =if(e9<$C$5,1,0) • In column K, calculate dummy variable indicating households that will be poor after the price change using =if(k9<$c$5,1,0) • Calculate indicator for changes in poverty status as poor after minus poor before. • Calculate average poverty rate before and after price change by calculating average of columns L and M

17. Exercise 2 Discussion • After a very large (80%) increase in price, there is only a very slight (1%) increase in poverty • What does this say about people in this country? • How can policy makers use this information?

18. Conclusions • NBR is a useful tool for understanding the effects of food price changes on households • High grain prices usually generate benefits for rural area overall … • … but benefits are concentrated among small number of net sellers, particularly large farmers • Many (most) rural households are net buyers of the main staple crop • Virtually all urban households are net buyers of staple crops • Poor urban households have largest negative NBR for staples and are hardest hit by food price increases

19. References • Deaton, A. 1989. Rice prices and income distribution in Thailand: a non-parametric analysis.” Economic Journal. 99(Conference): 1-37. • Minot, N. and Goletti, F. 2000. Rice market liberalization and poverty in Viet Nam. Research Report 114, International Food Policy Research Institute, Washington DC. • Ivanic, M. and W. Martin. 2008. Implications of higher global food prices for poverty in low-income countries. Policy Research Working Paper No 4594. World Bank, Washington, DC.