BACKGROUND

Increasing competition by nonprofit organizations provides blood donors with many options to engage themselves prosocially (e.g., by donating money or time). While most previous studies focused only on one form of donation, only a few studies analyzed two or more forms. This research gap is remarkable, as prior research has shown that a substantial portion of donors engage in more than one form of donation. In addition, studies have shown that donors' main reason for lapsing is switching to another donation form.
STUDY DESIGN AND METHODS

This study relies on longitudinal data from the German Socio‐Economic Panel. In total, 5640 (non)blood donors are analyzed over a period of 5 years, alongside their engagement in four forms of prosocial behavior: money donations, taking care of persons in need, volunteer work, and citizens' initiatives. We control for sociodemographic, psychographic, and health‐related factors and rely on propensity score matching to reduce selection effects often observed in the blood donation context.
RESULTS

There are significant differences between blood donors and nondonors in their engagement in prosocial behaviors. Blood donors (vs. nondonors) are more likely to engage in other prosocial behavior forms, namely, donating money, volunteering, and participating in citizens' initiatives. If people start donating blood, they also are more likely to act in other prosocial ways, namely, donating money and volunteering. If people stop donating blood, they also are more likely to stop other forms of prosocial behavior, namely, volunteering and participating in citizens' initiatives.
CONCLUSION

This study provides new insights into blood donors' prosocial behavior. While most previous studies neglected blood donors' engagement in other prosocial behaviors, this study highlights the fact that blood banks need to be aware of blood donor switching behavior between all prosocial behavior forms. As most blood banks also are providing other types of donations forms, they can use this knowledge and cross‐recruit blood donors to engage in other forms of prosocial behavior.