Application of Web-based Respondent

Driven Sampling to Foreign-Born

Korean Americans

Sunghee Lee, Ai Rene Ong, Chen Chen,

Michael ElliottUniversity of Michigan

Health and Life

Study of Koreans

This study was funded by the National Science Foundation [grant number SES-1461470, PI: Lee].

Respondent Driven Sampling (RDS)

• Proposed by Heckathorn (1997, 2002)

• Sampling based on▫ Chain-referral through social networks and

▫ Actual recruitment by participants using coupons

( Researchers have little control over and little

information about selection)

• Potentially useful locating rare groups

• Popular usage in public health ▫ ~$100 million research funds by NIH as of 2011

▫ Used for National HIV Behavioral Surveillance by CDC

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RDS Visualization – 1

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Hypothetical

Network Population

Nodes

Edges

RDS Visualization – 2

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Seeds

(Ego)

Alters (Peers)

Coupons

Chains RecruitersRecruits

Degrees

Waves

Long chain: Memoryless

Markov process

Two Types of RDS Recruitment Chains

Type 1

2 Seeds Sample size=20

Type 2

2 Seeds Sample size=20

Note: Each dot represents a participant;

Shade of dots: Character similarities;

Arrow: Recruitment direction.

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Web-RDS & Racial/Ethnic Minorities

•Why RDS?

▫ Racial/ethnic homophily

•Why Web?

▫ Lower constraints with language and geography

coverage

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This Study

• Utilities of Web-RDS for recruiting immigrants

• Data quality

▫ Geographic coverage

▫ Estimates on a series of socio-demographic, health status and healthcare access

Benchmarks available

• Dynamics in recruitment

▫ Recruitment patterns

▫ Recruitment cooperation through coupon use and follow-up survey

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Data Quality

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Health & Life Study of Koreans (HLSK)

• Web RDS ▫ Foreign-born Korean Americans in Los Angeles County

(LA) and State of Michigan (MI)

▫ June 2016 – March 2018

▫ Recruitment coupons Up to 2 coupons issued/participant

Delivered to email, text or messaging app

▫ Incentive: $20 for the main survey; $5 per recruit;

$5 for the follow-up survey Up to $35

▫ LA: n=360 (follow-up n=142)

▫ MI: n=279 (follow-up n=124)

▫ Benchmarks: American Community Survey (ACS);

California Health Interview Survey (CHIS)

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Geographic Distribution

• LA Maps

•MI Maps

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HLSK vs. ACS for LA

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HLSK vs. ACS for MI

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Dynamics in Recruitment

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Health & Life Study of Koreans (HLSK)

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Data Collection Progress

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669

522

360

279

131

92

Recruitment Patterns

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Actual Coupon Use

• 1191 issued 461 redeemed

(34.9% redemption rate)

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No. Redeemed Coupons

0 1 2

n 355 152 132

No. Is

sued

Coupons 0 32 -- -- --

1 23 56.5% 43.5% --

2 584 53.1% 24.3% 22.6%

Profile of Intended vs. Actual Recruits

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Intended Recruits of

All Recruiters

(n=1138)

Intended Recruits of

Successful Recruiters

(n=539)

Actual Recruits

(n=415)

Age

18-29 years old 32.6% 30.4% 34.1%

30-39 years old 25.2% 26.4% 25.4%

40-49 years old 20.8% 21.0% 21.0%

50-59 years old 15.4% 16.1% 14.0%

≥60 years old 5.9% 6.1% 5.6%

Gender

Male 43.4% 42.9% 41.2%

Female 56.6% 57.1% 58.8%

Recruiter-Recruit Relationship

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Intended Recruits

of All Recruiters

(n=1138)

Intended Recruits of

Successful Recruiters

(n=539)

Recruiters Reported

by Recruits

(n=415)

Feel close to 88.9% 92.4% 87.0%

Weekly interaction -- -- 78.4%

Relationship Type

Family 28.2% 36.5% 53.4%

Spouse 10.5% 15.2% 21.6%

Parent 7.0% 11.1% 7.7%

Sibling 6.0% 5.4% 7.9%

Relative 4.7% 4.8% 16.2%

Non-Family 71.7% 63.5% 46.8%

Friend 45.9% 41.3% 31.0%

Romantic partner 4.0% 4.6% 3.8%

Acquaintance 14.2% 10.6% 5.6%

Colleague 7.6% 7.0% 6.2%

Dynamics in Coupon Distribution

(From follow-up participants, n=266)

•When? Within 3 days (50.0%)

Within a week (77.4%)

•Mode? Kakaotalk (48.9%)

Email (41.1%)

•Word of Mouth? Incentives (87.0%)

Korean focus (72.6%)

Web mode (50.9%)

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Implications – 1

• Potential of RDS

▫ Reasonable geographic coverage

▫ Young, highly educated recent immigrants

▫ Recruit harder-to-reach groups

▫ Blend RDS data with existing probability data

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Implications – 2

• Challenges with RDS

▫ Sampling affected by nonsampling errors

▫ Recruitment noncooperation ~30% coupon redemption rate; Chains died out Need to issue ≥3 coupons/R

(Best to apply a one-size-fits-all rule?)

▫ Social relationship matters for recruitment

success

Participants intend to recruit close peers

Recruits report frequent interactions with recruiters

HLSK: Relationship type (family)

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Future Directions

• RDS as a practical and reproducible data

collection method

• RDS design

▫ Total survey error

▫ Generate data mirroring critical assumptions

▫ Test design features increasing Rs’ recruitment

cooperation through randomized experiments

▫ Adaptive survey design

▫ Standardization and transparency

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Thank you

Questions?

sungheel@umich.edu

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