OBJECTIVES: Stem cell transplants are used as a last resort treatment for blood cancer. While a quarter of patients can receive a transplant from a relative's stem cell donation, most rely on voluntary donors. However, the likelihood of finding a match between donor and patient is low, necessitating a large pool of registered donors. Despite efforts to increase the donor pool through public advertising and recruitment events, 10% of patients still cannot find a suitable donor. This study examines the impact of altering the registration choice frame to increase the number of potential donors.

METHODS: We conducted an online and field experiment. In the online experiment, we adapted an interactive decision game for stem cell donor registration and compared registration rates for two different choice frames and two information treatments. In the second part, participants were asked if they wanted to register with a German donor center. We replicated the different choice frames from the online experiment for participants to request a registration link and also implemented a treatment where participants received buccal swab registration sets at their participation addresses.

RESULTS: From March to September 2022, 309 subjects participated in the experiment. Preliminary results show that both default and information treatments affected registration decisions in the lab. Further analyses will examine the influence of personal characteristics and dynamics within the simulated decision game.

CONCLUSIONS: Our findings can improve stem-cell donor registration decision design and potentially increase registration rates. Additionally, our unique setup allows us to measure the external validity of decisions in laboratory experiments, contributing to experimental literature on donation behavior.