Collective Philanthropy: Describing and Modeling the Ecology of Giving [pdf] [PLOS One]

Figure 1:

Gift size distributions for a range of institutions. The reported alpha and gamma were fitted to the region indicated by solid grey line, and the 95% CI of this fit, as well as year for which the fit is plotted, are included for each organization. The ranges over which the data were fit was chosen empirically; other approaches were found to be inconsistent (see Supplementary). A. Health Care: Mt. Sinai Hospital, 2010 had gamma = 2.02 plus/minus 0.10. B. Higher Education (Medical): Einstein School of Medicine, 2010 had gamma = 1.80 plus/minus 0.06. C. Higher Education (General): University of Vermont, 2010 had gamma = 1.81 plus/minus 0.05. D. Combined Purpose: United Way, 2010 had gamma = 2.47 plus/minus 0.09. E. Cultural: echo Aquarium and Science Center, 2009 had gamma = 1.73 plus/minus 0.15. F. Performing Arts: Flynn Theater, Burlington VT, 2010 had gamma = 2.09 plus/minus 0.05. Later in Fig. 13, we show similar data for an anonymous religious institution. Dates and amounts of all contributions were collected over time periods ranging from 2 years to 37 years. United Way and Mt. Sinai Hospital were the only organizations able to ensure that annual donor gift amounts are ected that year's total of donations by a single donor, rather than individually posting multiple gifts made by a single donor during that year.