1. The Luxembourg Income Study at Age 25
Providing Protected Microdata for the Analysis of Income, Employment and Wealth
Prepared for 56th Session of the
International Statistical Institute
24 Aug 2007

2. Outline Background Microdata Access LIS Data Security
Data Comparability

3. LIS Background Research center and microdata archive
Founded founded in 1983
International board of advisers
Financed by the participating countries
supplemental funding from the Luxembourg government and outside grants

4. LIS Background Staff Janet Gornick, Director
Professor of Political Science and Sociology
Baruch College, CUNY, U.S.A.
Markus Jantti, Research Director
Professor of Economics
Åbo Akademi University, Finland
Two offices
Luxembourg & U.S.
7 researchers and statisticians

5. Goal Promote comparative social science and policy research
Provide secure method for microdata access
LIS handles contact with data providers
Administration
Confidentiality agreements
Translation
Allows access not available to individual researchers
Country-specific privacy restrictions
Harmonise social and economic microdata
Standardised variable names promote ease of use
Content selection improves comparability

6. LIS Data Base Socio-economic micro-data Availability
private households
representative of the country population
Availability
6 waves
every 5 years starting in 1980
every 4 years starting with Wave VI (2004)
historical data base pre-1980
32 countries
expanding in Wave VI and beyond
150 current data sets
19 Wave VI data sets ready to be lissified

7. LIS Data Base

8. LIS Research
Used by over 1,500 researchers in 35 countries to analyze economic and social policy effects
poverty
income inequality
employment status
wage patterns
gender inequality
family formation
child-wellbeing
health status
immigration
political behavior and public opinion
women’s economic status
economic gender inequality

9. LIS Research Articles in major academic journals
Economics
Political science
Sociology
Well-known for use in measuring comparative poverty and income inequality
Used to inform OECD, UN, World Bank
Instrumental in changes in child policy in Great Britain
Bradshaw and Chen (1997)

10. Microdata Access Public Access Restricted Access Key Figures
Working Paper Series
User Support
Restricted Access
Microdata Programming Access (“LISsy”)
Web Tabulator
Visiting Scholar Program
Workshops

11. LISsy System Purpose Results Allow for user-programmed analysis
Programs run directly on microdata
Use any of 3 popular statistical packages
Stata, SAS, SPSS
Fully automated system running 24/7
Results
Output from user programs
Extent of analysis limited only by software functionality and user ability
Not confined to pre-packaged tables or analyses

12. Web Tabulator Purpose Results
Provide user-friendly access to microdata
design and create tables derived from LIS datasets
no need for knowledge of statistical packages
secure internet interface
Results
User-created cross-national cross-tabulations
view on-line
export results to text file

13. Visiting Scholar Program
Purpose
Provide direct access to subset of LIS microdata
Individual software need
Analysis requires viewing individual records
Direct access to LIS experts
Application process
LIS pays all expenses
Results
Individually-tailored analysis
Knowledge and guidance of LIS staff

14. Workshops Purpose Results Provide intensive training for new users
Annual summer workshop
25-30 researchers
Week-long training course
Taught by entire staff
Outside experts and researchers
Country workshops
Individually-tailored workshops
LIS staff travels to researchers

15. LIS Data Security Users must meet specific criteria
Available for social science research purposes only
No private or commercial use is permitted
Researchers must be:
Working for or attending an academic organization
Member of government or non-profit organization research departments

16. LIS Data Security Users must register to analyze data
Describe research objectives and projected length of project
Sign a confidentiality pledge
Not to attempt to identify individuals
Not to attempt to copy or list individual records
Re-register annually
update contact information
renew confidentiality pledge

17. LIS Data Security Accessed by users through e-mail
system is not in direct contact with the microdata
Database cannot be downloaded

18. LIS Data Security Users submit requests by e-mail LISsy :
Clearly identifies sender
LISsy :
Accepts requests from server
Checks request
Identity
Registration
Security & confidentiality issues
Sends requests to batch processing
Checks output for confidentiality issues
Returns completed listings by
Only to the address given during the registration process
Listings only returned with aggregated information

19. Balancing Access and Data Security
Provides user-friendly microdata access
Remote access
3 popular statistical packages
Individual-specific analysis
Speed
Maintains confidentiality and security
Country-specific requirements
General issues
Registration and identification of user
User output

20. Comparability Challenges
Country : Different institutions/societal norms across countries
Surveys
Different types of original collection instrument
Level of detail of information collected differs
Time : Changes in institutions and surveys
Technical differences
Weighting procedures
Treatment of missing values, imputation methods
Topcoding
Differences in confidentiality requirements

21. LIS Golden Rules Maximise comparability Ease of use Allow flexibility
Set clear definitions for each variable
Follow the definitions as much as possible
Preserve cross-sectional comparability first and comparability over waves after
Ease of use
Create standardised codes within variables
Allow flexibility
Keep country-specific detail to allow users to redefine to suit their specific needs
Preserve as much detail as possible
Document
Warn users of all deviations from the ideal definition

22. On-line Documentation
Survey information
Technical information on the original survey
Data collection methods, reference period, sample, sampling errors etc
Lissification tables
Precise definition and contents of each LIS variable
Explains deviations from ideal variable definitions
Basic descriptives
Unweighted descriptive statistics of each variable
Institutional information
exhaustive information on the tax and transfer programs corresponding to microdata variables

23. Additional Help Additional comparative databases
country-level policy indicators
welfare states database
family policy database

24. Future Challenges Expansion
New countries
Less likely to conform to existing definitions
Need to add more country-specific information in addition to core LIS variables?
What is the right mix of data expansion and comparability?