https://www.sciencedaily.com/releases/2019/04/190415143928.htm

Researchers from UBC Okanagan, University of Melbourne and the University of Guelph found that changing the deadline for donations closer to tax time increased donations by nine per cent.

The team used a 2010 policy experiment in Quebec as their basis. As a way to encourage giving in support of Haiti earthquake relief, the province allowed residents to claim their donations early.