1 Division of Translational Research & Applied Statistics, Department of Public Health Sciences, University of Virginia, Charlottesville, Virginia. Electronic address: nwages@virginia.edu.
2 Department of Biostatistics, University of Michigan, Ann Arbor, Michigan.
3 Department of Biostatistics, University of Pittsburgh School of Public Health, Pittsburgh, Pennsylvania.
4 Department of Biostatistics, University of Michigan, Ann Arbor, Michigan; Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan.