1. Louis Stokes Cleveland VA Medical Center, Cleveland, OH 44106, USA
2. Case Western Reserve University, Cleveland, OH 44106, USA
3. Institute for Biomedical Informatics, University of Kentucky, Lexington, KY 40536, USA
4. Quality Management Service, VHA Greater Los Angeles Healthcare System, Los Angeles, CA 90073, USA
5. Department of Statistics, George Mason University, Fairfax, VA 22030, USA
6. Department of Neurology, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA