Major charity appeals can bring in hundreds of millions of dollars. But many worry that these efforts shift money away from other charities or merely move donations forward in time.

In a paper in the American Economic Journal: Economic Policy, authors Kimberley Scharf, Sarah Smith, and Mark Ottoni-Wilhelm found that charity fundraisers do in fact lift donations without being offset elsewhere. The findings show that fundraisers can increase the size of the overall charitable pie.

However, major appeals still have some spillover effects on the timing of donations to other charities. As a result, Smith says that organizations should focus on sustaining fundraising efforts in order to ensure that funds don't disappear in the longer term.

Sarah Smith recently spoke with Tyler Smith about how donors respond to major charity appeals in the United Kingdom and what fundraisers should take away from the results.