1. 1 Record Linkage for Epidemiologic Research: Accessing Linked data at the NCHS Research Data Center Christine S. Cox NCHS Data Users Conference July 12, 2006 U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES Centers for Disease Control and Prevention National Center for Health Statistics

2. 2 Administrative records Linked Data File NCHS Surveys What is Record Linkage?

3. 3 NCHS Linked Data: Major Activities Mortality Mortality National Death Index National Death Index Health Care Utilization and Costs Health Care Utilization and Costs Medicare Data Medicare Data Retirement and Disability Retirement and Disability Social Security Data Social Security Data

4. 4 NCHS Linked Data: Mortality Eligibility status Eligibility status Assigned vital status Assigned vital status Date of death Date of death Age at death Age at death Underlying and multiple causes of death Underlying and multiple causes of death Adjusted sample weights Adjusted sample weights

5. 5 Research Potential of Linked Mortality Data Living and Dying in the USA: Behavioral, Health, and Social Differentials of Adult Mortality RG Rogers, CB Nam, RA Hummer A Semiparametric Analysis of the Body Mass Index’s Relationship to Mortality JT Gronniger The Income-Associated Burden of Disease in the United States P Muennig, P Franks, H Jia, E Lubetkin and MR Gold Excess Deaths Associated with Underweight, Overweight, and Obesity KM Flegal, BI Graubard, DF Williamson; MH Gail JAMA. 2005;293:1861-1867.

6. 6 NCHS Linked Data: Medicare Medicare entitlement and health care utilization and payment data for 1991-2000 Medicare entitlement and health care utilization and payment data for 1991-2000 Denominator file Denominator file MEDPAR Inpatient hospitalization MEDPAR Inpatient hospitalization MEDPAR Skilled nursing facility MEDPAR Skilled nursing facility Hospital outpatient Hospital outpatient Home Health Care Home Health Care Hospice Hospice Carrier (physician/supplier Part B file) Carrier (physician/supplier Part B file) Durable Medical Equipment Durable Medical Equipment

7. 7 Research Potential of Linked Medicare Data Examine risk factors for health conditions Examine risk factors for health conditions Examine reliability of survey data Examine reliability of survey data Examine survey report of disability with program participation eligibility criteria Examine survey report of disability with program participation eligibility criteria Compare survey reported health conditions to claims records Compare survey reported health conditions to claims records Examine disparities in Medicare service utilization Examine disparities in Medicare service utilization

8. 8 NCHS Linked Data: Retirement/Disability Social Security data from Retirement, Survivors, and Disability Insurance (RSDI) and Supplemental Security Insurance (SSI) programs Social Security data from Retirement, Survivors, and Disability Insurance (RSDI) and Supplemental Security Insurance (SSI) programs Master Beneficiary Record (MBR) Master Beneficiary Record (MBR) 1962-2003 1962-2003 Payment History Update System (PHUS) Payment History Update System (PHUS) 1984-2003 1984-2003 Supplemental Security Record (SSR) Supplemental Security Record (SSR) 1974-2003 1974-2003

9. 9 Research Potential of Linked Social Security Data Examine reliability of survey information for SSA program participation and benefits Examine reliability of survey information for SSA program participation and benefits Compare the health characteristics of those who take early (age 62) Social Security benefits to those who postpone benefits Compare the health characteristics of those who take early (age 62) Social Security benefits to those who postpone benefits Policy analysis using validated survey data Policy analysis using validated survey data Predicting the number of people who will become disabled based upon survey reported health conditions Predicting the number of people who will become disabled based upon survey reported health conditions Determining whether current disability entitlement funding levels will be adequate as the population ages Determining whether current disability entitlement funding levels will be adequate as the population ages

10. 10 Summary NCHS Data Linkage XXNNHS 1985 XXXNHANES III XXNHANES II XXXNHANES I XXXLSOA II XXXNHIS 1994-1998 XNHIS 1986-2000 Retirement & Disability (SSA) Medicare (CMS) Mortality (NDI)

11. 11 www.cdc.gov/nchs/r&d/nchs_datalinkage/data_linkage_activities.htm

12. 12 Why can’t you just give me the data? NCHS does not “own” the linked administrative data NCHS does not “own” the linked administrative data NCHS data confidentiality rules prohibit the release of potentially identifiable data – special considerations concerning the protection of linked data NCHS data confidentiality rules prohibit the release of potentially identifiable data – special considerations concerning the protection of linked data The RDC is the only option for access for now…. The RDC is the only option for access for now….

13. 13 Overview: Data Access Procedures Proposal Requirements Proposal Requirements Access Methods Access Methods Helpful Tips Helpful Tips Where to get help? Where to get help?

14. 14 Proposal Requirements Proposal is evaluated by review committee Proposal is evaluated by review committee Review criteria Review criteria Scientific and technical feasibility Scientific and technical feasibility Availability of RDC resources Availability of RDC resources Disclosure risk for restricted information Disclosure risk for restricted information The extent to which project is in accordance with the mission of NCHS The extent to which project is in accordance with the mission of NCHS Special note: NCHS does not try to determine if proposals are duplicative Special note: NCHS does not try to determine if proposals are duplicative

15. 15 Proposal Requirements Cover letter Cover letter Project title Project title Abstract (maximum 300 words summarizing project) Abstract (maximum 300 words summarizing project) Full contact information Full contact information Institutional affiliation Institutional affiliation Mail address, phone, email Mail address, phone, email Dates of proposed time at RDC (or indication of using remote access) Dates of proposed time at RDC (or indication of using remote access) Source of funding for proposed research Source of funding for proposed research

16. 16 Proposal Requirements Study background Study background Key study questions or hypotheses Key study questions or hypotheses Public health benefits Public health benefits Methods Methods Analytic approach and statistical methods Analytic approach and statistical methods Statistical software requirements Statistical software requirements Description of intended output for nondisclosure review, e.g. Description of intended output for nondisclosure review, e.g. Table shells Table shells Model equations Model equations Test statistics that researcher plans to remove from RDC Test statistics that researcher plans to remove from RDC

17. 17 Proposal Requirements Explanation of why restricted data are needed, e.g. describe why publicly available data are insufficient Explanation of why restricted data are needed, e.g. describe why publicly available data are insufficient Summary of data requirements to be included in analytic file Summary of data requirements to be included in analytic file Identification of sample Identification of sample Identification of variables Identification of variables Description of additional data to be supplied by researcher to be merged with NCHS or other data source (must clearly identify source of other data) Description of additional data to be supplied by researcher to be merged with NCHS or other data source (must clearly identify source of other data)

18. 18 Proposal Requirements: Appendices Current Curriculum Vitae or resume for each investigator Current Curriculum Vitae or resume for each investigator Data dictionary – complete listing of specific data requested and its source(s) and indicate if public use or restricted access variables Data dictionary – complete listing of specific data requested and its source(s) and indicate if public use or restricted access variables specific files and years specific files and years sample sample variables (dependent, independent, matching/linking) variables (dependent, independent, matching/linking)

19. 19 Proposal Requirements: Appendices For remote-access applicants For remote-access applicants Description of the computer and email system to be used to receive output Description of the computer and email system to be used to receive output Security provisions for the computer and email systems Security provisions for the computer and email systems For students For students Letter from department chair or academic advisor stating that student is working under the direction of the department Letter from department chair or academic advisor stating that student is working under the direction of the department

20. 20 Overview: RDC Data Access Procedures Proposal Requirements Proposal Requirements Access Methods Access Methods Helpful Tips Helpful Tips Where to get help? Where to get help?

21. 21 Access Methods Once approved, three methods to access restricted data Once approved, three methods to access restricted data on-site - use local computing resources in the NCHS RDC, Hyattsville, MD on-site - use local computing resources in the NCHS RDC, Hyattsville, MD remote – submit programs electronically to be executed in the RDC with output returned by email remote – submit programs electronically to be executed in the RDC with output returned by email staff assisted – RDC staff provide on-site programming for off-site approved researchers staff assisted – RDC staff provide on-site programming for off-site approved researchers For all methods of access, restricted data files remain in RDC and output is inspected for disclosure violations For all methods of access, restricted data files remain in RDC and output is inspected for disclosure violations

22. 22 On-Site Access RDC staff constructs necessary data files, including merged user data RDC staff constructs necessary data files, including merged user data Most statistical packages available with sufficient lead time Most statistical packages available with sufficient lead time Output subject to disclosure review Output subject to disclosure review Open only during normal working hours Open only during normal working hours

23. 23 Remote Access Method RDC staff constructs necessary data files, including merged user data RDC staff constructs necessary data files, including merged user data SAS programs only (certain procedures and functions not allowed) – additional software options expected SAS programs only (certain procedures and functions not allowed) – additional software options expected Both submitted programs and output undergo a programmed disclosure limitation review Both submitted programs and output undergo a programmed disclosure limitation review

24. 24 RDC Staff-assisted Programming Method Subcontract with the RDC staff to perform programming tasks Subcontract with the RDC staff to perform programming tasks Useful for those planning to use statistical software not available for the remote system and who are not able to travel to the RDC facility Useful for those planning to use statistical software not available for the remote system and who are not able to travel to the RDC facility Cost is estimated for each research project Cost is estimated for each research project

25. 25 Overview: RDC Data Access Procedures Proposal Requirements Proposal Requirements Access Methods Access Methods Helpful Tips Helpful Tips Where to get help? Where to get help?

26. 26 RDC Helpful Tips Be clear about research and data requirements (helps to determine feasibility of project) Be clear about research and data requirements (helps to determine feasibility of project) Clearly identify the sample to be included in the analytic file Clearly identify the sample to be included in the analytic file Provide data dictionaries for both Provide data dictionaries for both Public use data Public use data Restricted data Restricted data Provide examples of expected output Provide examples of expected output

27. 27 Overview: RDC Data Access Procedures Proposal Requirements Proposal Requirements Access Methods Access Methods Helpful Tips Helpful Tips Where to get help? Where to get help?

28. 28 Visit the RDC at: www.cdc.gov/nchs/r&d/rdc.htmwww.cdc.gov/nchs/r&d/rdc.htm or email: rdca@cdc.gov