Gaining Acceptance for the Use of Multiple Imputation in the
Analysis of Public Data
Traffic Records ForumJuly 14, 2003
Ted DonnellyRI Department of Health
Do I look like a salesman?
Do I look like a salesman?
• Career in public service
Do I look like a salesman?
• Career in public service
• Skill set is technical
Do I look like a salesman?
• What is my product?
Do I look like a salesman?
• What is my product?
• Who are my customers?
Meteorology
• Rainfall
• Wind resources
• Application to GIS layer
Chandra X-ray of the Crab Nebula
Departments of AstroPhysics and Statistics
Harvard University
Wildfires in the American West
Oak Ridge National Laboratory
Important government applications where imputation is used
• US Census 2000• Survey of Income and Program Participation
(Census Bureau)• Behavioral Risk Factor Surveillance System
(CDC)• Fatality Analysis Reporting System (NHTSA)• Crash Outcome Data Evaluation System
(NHTSA)
Winners and Losers
• Utah vs. Evans II
• Additional House seat was assigned to NC
• Use of imputation to improve population estimates upheld by U.S. Supreme Court
Do I look like a salesman?
• Who are my customers?
Customers
• Demographers and epidemiologists familiar with Census Bureau methods
Customers
• Physical scientists use these techniques routinely in graphic representations
Customers
• Survey researchers find MI useful in analysis of incomplete surveys and to calculate improved sample weights
Customers
• State legislators
• Data Managers
• Governor’s Highway Safety Representative
State legislators
• part-time elected representatives
• educated and politically astute
• familiar with the results of survey research, especially opinion polls
Pew Research Center
“Based on the total sample, one can say with 95% confidence that the error attributable to sampling and other random effects is plus or minus 3.5 percentage points.”
Data managers
• Develop system for purposes that use storage and retrieval
• May have sophisticated skills but little experience with research
• Primarily concerned with integrity and usefulness of the data
Governor’s Highway Safety Representative
• Bring HSR along with use of MI in FARS and CODES
• Technical staff may be familiar with MI
• Be available for follow-up consultation
Additional Concern: Changing public data sets
• multiple imputation is not a method for changing data
• tool for improving estimates in the analyses that make data meaningful and error estimable
