The impact of temporary deferrals on future blood donation behavior across the donor life cycle.

Blood banks that seek to overcome the negative effect of deferrals should be aware that this effect varies with donor experience and with the number of previous deferrals. Our results suggest that blood banks should focus on early-stage donors who are deferred because the negative deferral effect is stronger for more experienced donors. At the same time, blood banks should be careful with donor groups who have experienced deferrals in the past because every additional deferral demotivates future donation behavior. Overall, researchers should be careful to correct for endogeneity because our results suggest that ignoring these effects could lead to substantial underestimation of the negative deferral effect.