What’s in a Name? Accounting for Naming Conventions in NCHS Data Linkages

1. What’s in a Name?Accounting for Naming Conventions in NCHS Data Linkages Eric A. Miller National Center for Health Statistics (NCHS) 2012 FCSM Statistical Policy Seminar December 4, 2012

2. “Two men say they’re Jesus. One of them must be wrong.” Mark Knopfler, Dire Straits

3. What Does This Have to do With Data Quality? • One reason for data sharing is data linkage • Assessing the quality of linked data is different from assessing a standalone dataset • The quality of variables from a specific source doesn’t matter if the linkage is poor • Problems with linkage can produce poor quality data • Are the data fit for use? + Are the data fit for linkage?

4. Names • Names are commonly used in data linkages • Important to account for name differences and naming conventions to produce a high quality linked data file

5. Quick Background on Data Linkage • Deterministic • Exact match on linkage variables • Frank ≠ Francis • Probabilistic • Accounts for imperfect data • Probability of a match • Frank ≈ Francis

6. Caveats of Data Linkage • It’s not perfect Prince ? Prince Prince Rogers Nelson Some things are out of our control!

7. Caveats of Data Linkage • Varying levels of quality for linkage variables can substantially increase workload • Clean-up, reformatting • Clerical review • Analysis of insufficiently linked data can produce biased estimates

8. Example - Hispanic Paradox • Despite having a higher risk profile, Hispanics have been found to have lower mortality rates compared to non-Hispanic whites Markides and Coreil (1986). Public Health Reports; 101: 253-265

9. Mortality Rate per 100,000 Among Women in 1986-1990 National Health Interview Survey Linked to 1991 National Death Index Liao et al. (1998). Mortality Patterns among Adult Hispanics: Findings from the NHIS, 1986 to 1990. AJPH.

10. Potential Reasons for Paradox • Health selective immigration • Salmon bias (return migration) • Advantageous health behaviors and social support • Data quality / Insufficient linkage

11. Potential Reasons for Paradox • Data quality / Insufficient linkage • Naming conventions for Hispanics differ from other US populations • Use of mother’s and father’s surname • May not have single middle name • Less likely to have social security number • Especially among older adults and foreign born

12. Percent of “True” Matches for Hispanics and Non-Hispanic Whites by Foreign-Born Status Class 1: records agree on at least 8 digits of SSN as well as first and last name, middle initial, and birth year (+/- 3 years) Joseph Lariscy. Differential record linkage by Hispanic ethnicity and age in linked mortality studies: Implications for the epidemiologic paradox. J of Aging and Health (2011); 23: 1263-1284.

13. What does this have to do with NCHS? • NCHS Record Linkage Program • Links survey data with data collected from administrative records • Designed to maximize the scientific value of the NCHS population-based surveys • Examine factors that influence chronic disease, disability, health care utilization, morbidity, and mortality

14. Linked NCHS surveys • National Health Interview Survey (NHIS) • 1999-2004 NHANES, NHANES III, and NHANES II • NHANES I Epidemiologic Follow-up Study (NHEFS) • The Second Longitudinal Study of Aging (LSOA II) • National Nursing Home Survey (NNHS)

15. Linked Administrative Records • National Death Index • Medicare and Medicaid enrollment and claims • Social Security Administration Retirement and Disability • Pilot projects • Florida Cancer Data System • Texas Supplemental Nutrition Assistance Program (SNAP)

16. Case Study: NCHS Survey linkage with the NDI • National Death Index (NDI) • A national file of identifying death record information (beginning with 1979 deaths) • Every four years we send a file of survey participants to NDI to conduct a linkage and identify participant deaths • We take additional steps to try and improve the linkage

17. NDI Matching Algorithm • Social Security Number • First name • Middle initial • Last name • Month of birth • Year of birth • Sex • Father’s surname • State of birth • Race • State of residence • State of birth • Marital Status

18. Unweighted percent of NHIS sample adults aged 18 or older, refusing to provide SSN, 1997-2009

19. NCHS Record Linkage Program • To make sure we provide research quality data, we spend a lot of time processing the data to increase the chance of finding a true match • Try to increase the number of matches while minimizing false matches • Addressing name clean-up and naming conventions is a major activity

20. Methods – Name Clean-up • Fix invalid characters • Compress spaces • Remove titles/descriptors/suffixes • e.g. Mr., baby, jr. • Linkage uses NYSIIS phonetic codes • Accounts for misspellings or unusual spellings

21. Methods – Name Clean-up • Create alternate records • Sent with original record • Among women substitute surnames for last name • Nicknames (using a look-up table) • Substituting Elizabeth for Beth

22. Nickname Lookup Table Example: If first name=‘Andy’ then alternate record first name=‘Andrew’

23. Methods – Name Clean-up • Accounting for Hispanic and Asian naming conventions • Hispanic • Hispanic nickname lookup table • switch middle and last • Asian • switch first and last

24. Hispanic Lookup Table

25. Alternate Records Example

26. Conclusions • Care needs to be taken to avoid false links • Alternate records increases the number of potential matches • If two men claim they’re Jesus, they can both be wrong • Need a higher level of scrutiny to determine that a pair of records match

27. Conclusions • Accounting for name differences and naming conventions improves quality of the linked-data product • Hope our efforts to account for Hispanic and Asian naming conventions reduces potential bias • Need to evaluate

28. Important Considerations • How are names are collected? • How are the names recorded? • More likely to have formal names versus nicknames? • Surveys may differ from official documents • Are maiden names (surnames) available? • Are there consistent rules for recording names?

29. Acknowledgements • Dr. Jennifer Parker • Dr. Dean Judson Thank you