For future research explaining charitable giving (i.e. philanthropy) Bekkers and Wiepking (2011) provide a basic theoretical framework. Based on a literature review of more than 500 articles they identify eight mechanisms as the most important forces that drive charitable giving: (a) awareness of need; (b) solicitation; (c) costs and benefits; (d) altruism; (e) reputation; (f) psychological benefits; (g) values; (h) efficacy. The quality of research is increased by explicitly testing these mechanisms with adequate statistical models (Bekkers & Wiepking, 2011).
Bekkers, R. and Wiepking, P. (2011). A Literature Review of Empirical Studies of Philanthropy: Eight Mechanisms That Drive Charitable Giving. Nonprofit and Voluntary Sector Quarterly, 40(5). 924-973