Departement Wirtschaftswissenschaften / Politische Ökonomie (Stutzer)
Many private and public organizations rely on voluntary contributions to
provide public goods. In order to sustain these organizations, the question arises
how the willingness to contribute can be maintained and further encouraged.
In our research, we study voluntary blood donations. These voluntary
contributions are necessary to keep up the highly developed medical services in
In study 1, we examine a decision framework in which people are
individually asked to either actively consent to or dissent from some prosocial
behavior. We hypothesize that confronting individuals with the choice of
whether to engage in a specific prosocial behavior contributes to the formation
of issue-specific altruistic preferences, while simultaneously involving a
commitment. The hypothesis is tested in a large-scale field experiment on blood
donation. We find that this “active-decision" intervention substantially
increases the actual donation behavior of people who had not fully formed
There is a longstanding concern that material incentives might undermine
prosocial motivation, leading to a decrease in blood donations rather than an
increase. This paper provides an empirical test of how material incentives
affect blood donations in a large-scale field experiment spanning three months
and involving more than 10,000 previous donors. We examine two types of
incentive: a lottery ticket and a free cholesterol test. Lottery tickets
significantly increase donations, in particular among less motivated donors.
The cholesterol test leads to no discernable impact on usable blood donations.
If anything, it creates a small negative selection effect in terms of donations
that must be discarded.