Migration and Household Surveys: Sampling Design Johan A. Mistiaen The World Bank DECDG Nairobi, kenya 11 December 2006

Sampling Design: 2 Approaches 1. Probability Sampling (PS) –Each member of the target population has a known, nonzero selection probability –Random sampling methods used 2. Non-Probability Sampling (NPS) –Based on subjective judgments –Require models to analyze and interpret Probability Sampling is generally preferred but depends… Probability Sampling is generally preferred but depends…

Considerations in Sampling Design 2 Key Challenges with Constructing Probability Samples for the Study of Migration and Remittances: 2 Key Challenges with Constructing Probability Samples for the Study of Migration and Remittances: 1. Sampling frames for population sub-groups that migrate, send or receive remittances are generally non-existent so they must be constructed; and 2. These sub-groups are typically “Rare Elements” in the population and is often equivalent to finding a needle in a haystack.

Research Gaps: PS vs NPS Approaches Basic Questions: Basic Questions: –What is the appropriate sampling technique under different circumstances? Migrants, Non-Migrants and Return Migrants Migrants, Non-Migrants and Return Migrants Remittance Senders vs. Recipients Remittance Senders vs. Recipients Addressing endogeneity Addressing endogeneity –What are the trade-offs in terms of: Bias (sampling and non-response), Bias (sampling and non-response), Study Costs Study Costs Implementation Time Implementation Time

Research Project: The Brazil Nikkei Household Survey Objectives: Objectives: –Ascertain key determinants, constraints, socio-economic and welfare impacts of international migration by Japanese- Brazilians to, settlement in and return from Japan to inform development policy; –Test 3 different sampling approaches for survey bias trade-offs

Research Project: The Brazil Nikkei Household Survey Background Facts: Background Facts: 1.Brazil is home to about 1.3 million Japanese descendents - Nikkei (migration started in 1908, the 6th generation is now being born); 2.Today approximately 275,000 Nikkei from Brazil live and work in Japan; 3.Remittances back to Brazil are estimated to be approximately US$ 2.2 billion annually (Ministry of Foreign Affairs, Government of Japan), almost equal to annual export value from Brazil to Japan; Survey Design Implications ! Survey Design Implications ! 4.The 1990 revision of Japan's Immigration Law allows for legal migration up and to third-generation Nikkei; 5.Nikkei in Brazil are frequently targeted for robbery by criminal gangs.

Sampling Design Challenge Needle-in-a-Haystack: Needle-in-a-Haystack: –About 1.4 million Japanese-Brazilians (target population) in Brazil which is less than 1% of the total population (177 million) => COSTS Geographically Clustered: Geographically Clustered: –Vast majority of target population resides in neighborhoods located in the states of Sao Paulo (54%) and Parana (26%). Source: 2000 population census Research Project: The Brazil Nikkei Household Survey

Research: The Brazil Nikkei Household Survey Test 3 Sampling Design Approaches: Test 3 Sampling Design Approaches: 1.Random Disproportionate Stratified Sampling (PS) 2.Snowball Sampling (NPS) 3.Aggregation Point Intercept Sampling (NPS)

Research: The Brazil Nikkei Household Survey 1.Random Disproportionate Stratified Sampling (PS) Census-based target clusters identified Census-based target clusters identified

Nikkei Target clusters in the State of Sao Paulo

Research: The Brazil Nikkei Household Survey 1.Random Disproportionate Stratified Sample (PS) Census-based target clusters identified Census-based target clusters identified Listing conducted in the PPS selected clusters Listing conducted in the PPS selected clusters Households randomly PPS sampled from lists Households randomly PPS sampled from lists F2F interviews by Nikkei enumerators F2F interviews by Nikkei enumerators Stratified by geography, migrant status and generational characteristics Stratified by geography, migrant status and generational characteristics Will yield benchmark PS Will yield benchmark PS

Research: The Brazil Nikkei Household Survey 2.Snowball Sample (NPS) 25 Nikkei Diaspora associations contacted to request “seed” households 25 Nikkei Diaspora associations contacted to request “seed” households 70 seed households identified via 20 Nikkei Diaspora associations 70 seed households identified via 20 Nikkei Diaspora associations Exhaustive surveying of the referral-chain network identified via the seed households to minimize bias (Heckathorn, 1997, 2002) Exhaustive surveying of the referral-chain network identified via the seed households to minimize bias (Heckathorn, 1997, 2002)

Research: The Brazil Nikkei Household Survey 3.Aggregation Point Intercept Sample (NPS) 11 fixed locations and 6 events identified in Sao Paulo 11 fixed locations and 6 events identified in Sao Paulo F2F interview using short 10 min questionnaire F2F interview using short 10 min questionnaire Interview for fixed time period (e.g., 2 hours) Interview for fixed time period (e.g., 2 hours) 2 interviewers: one conducts interview, other records number of potential respondents passing the location 2 interviewers: one conducts interview, other records number of potential respondents passing the location

Research Project: The Brazil Nikkei Household Survey Some Key Research Questions: Some Key Research Questions: 1.Compare data (identical questions) from the PS random sample with the population census and nationally representative household survey (often used to study migration/remittances) 2.Compare data from the 2 NPS with PS 3.Assess impact of migration/remittances by matching households across the legislation- induced generational control

Research Project: The Brazil Nikkei Household Survey Key Emerging Challenge: Key Emerging Challenge: 1.Non-Response: Attempt to minimize via (a) using Nikkei interviewers, (b) Nikkei Diaspora endorsement and (c) after F2F refusal, leave copy of questionnaire that can be mailed Completion of data collection in January 2007 Completion of data collection in January 2007 Draft research paper will be circulated in February 2007 Draft research paper will be circulated in February 2007