Examining the Effects of Data Quality and State-Level Variability on National Driver's Licensing Data

• Activity Number: 339
• Type: Contributed
• Date/Time: Tuesday, August 5, 2014 : 10:30 AM to 12:20 PM
• Sponsor: Government Statistics Section
• Author(s): Marc Paladini*+
• Companies: U.S. Department of Transportation
• Keywords: data quality ; government data ; trends ; public data ; variability ; drivers license

Abstract

The Federal Highway Administration (FHWA), an agency within the United States Department of Transportation, collects aggregate data about the number of people with a driver's license by age and gender from all 50 states and the District of Columbia. Recent reports have noted an apparent drop in licensing rates among young adults and teenagers that, if sustained, could have significant consequences on topics ranging from transportation planning and safety to the economy. Due to data quality issues, inconsistent reporting from states and changes in data collection parameters, some reports have questioned the feasibility of using the licensing data to monitor these trends. This research uses publically available, state based licensing data for 16 to 21 year olds from 1996 to 2011 to examine how state level variability can affect national trends. Potential anomalies, data errors and sources of variability are identified and approaches to aggregating and reporting licensing data are compared using non-parametric methods. Finally, issues with licensing data are discussed and recommendations for the future use of licensing data are made.