How perceptions of bone marrow donation costs affect donation behavior: survey evidence from a large donor registry.

Over the past three decades, advancements in collection methods for hematopoietic stem cell transplantation substantially reduced invasiveness and safety concerns. To what extent, however, registered donors are informed about extraction methods and how their beliefs drive their willingness to follow through with a donation is not well understood. Inaccurate beliefs about extraction methods may cause donors to overestimate their perceived cost, potentially reducing donations. In a survey with about 24,000 potential donors in Germany's largest stem-cell registry, we investigate how beliefs about extraction methods affect potential donors' willingness to follow through with a stem cell donation. We find widespread misconceptions about extraction methods, with many donors attributing a significant fraction of stem cell extractions to be coming from never-used methods. Importantly, a lack of knowledge and misconceptions about extraction methods persist among registered donors, often anchored to methods that prevailed at the time of registration. Exploring the link between donors' beliefs and their (stated) willingness to donate, we find that accurate beliefs about lower extraction costs correlate with a 2.2-2.9 percentage points higher willingness to donate, representing a 40% reduction in donor unavailability. Our results highlight the need for informational campaigns to correct donors' misconceptions and potentially save more lives among blood cancer patients.