To incentivize volunteers, charities award prizes to fundraisers in order to stimulate fundraising efforts. However, it is unclear how effective such incentives are because volunteers may be driven by non-pecuniary incentives. That is, monetary incentives may crowd out intrinsic motivators (charitability), resulting in a negative effect. 

A field experiment is conducted over a two-month period, involving an online fundraising campaign with over 300 volunteers assigned to different incentive conditions. A special website was designed for the fundraiser, where fundraiser created a web page for fundraising purposes, sending e-mail solicitations and receive donations.  As a result we were able to observe effort over time, different from previous research in which effort is a latent variable.  

We find that commission-based incentives increase current effort and funds raised (while  tournament incentives do not), but also resulted in a reduced intentions to volunteer in the future.  In addition, we find that effort mediates the impact of both intrinsic and extrinsic motivators on amount of funds raised.  Furthermore, effort has an important positive effect on intent to volunteer. As a result, charities may want to design fundraising events that require fundraisers to induce more effort.