1. 1Center on Philanthropy, Indiana University-Purdue University Indianapolis, Indianapolis, IN, USA
2. 2U.S. Government Accountability Office, Dallas, TX, USA
3. 3StataCorp, College Station, TX, USA
4. 4Bush School of Government and Public Service, Institute for Science, Technology and Public Policy, Texas A University, College Station, TX, USA
5. 5Bush School of Government and Public Service, Institute for Science, Technology and Public Policy, Texas A University, College Station, TX 77843-4350, USA