1. Research Associate Professor in the Survey Methodology Program (SMP), Survey Research Center (SRC), Institute for Social Research (ISR), University of Michigan, 426 Thompson Street, Ann Arbor, MI 48106, USA
2. Professor of Biostatistics at the School of Public Health and Research Professor in the Survey Methodology Program (SMP), Survey Research Center (SRC), Institute for Social Research (ISR), University of Michigan
3. Assistant Research Scientist in the Survey Methodology Program (SMP), Survey Research Center (SRC), Institute for Social Research (ISR), University of Michigan
4. Research Associate Professor in the Survey Methodology Program (SMP), Survey Research Center (SRC), Institute for Social Research (ISR), University of Michigan
5. Senior Survey Methodologist in the Center for Survey Methodology, Survey Research Division, RTI International, 3040 E. Cornwallis Rd., Research Triangle Park, NC 27709, USA
6. Head of Research on the Labor Market and Social Security Study at the Institute for Employment Research, Regensburger Str. 104, 90478 Nuernberg, Germany and Professor of Survey Methodology at the University of Bamberg, Feldkirchenstr. 21, 96052 Bamberg, Germany