Como aumentar o número de doadores de sangue?

Esse foi um exercício simples e despretensioso que eu fiz no curso recente do Dan Ariely no Coursera.

How to increase blood donation?

The problem I intend to address is: People who are first-time or eventual blood donors don’t have a clear mapping of the impact of their behavior on common good and don’t see the progress they make over time. Considering this audience and given that habit is not established, some possible forces can act as barriers, leading to demotivation and eventual interruption of their behavior: they may question the point of their effort, they may forget to come back to the blood center or they may not integrate the identity of a donor person into their general auto-concept.

Research shows that money can backfire as a motivator in blood donation or other pro-social behaviors (Ariely, Bracha & Meier, 2009; Bénabou and Tirole, 2005; Gneezy and Rustichini, 2000) – so monetary incentives are off limits to address the problem at hand. Also, Self-determination Theory (Deci and Ryan, 2002) shows that incentives in general, perceived as extrinsic motivators, can crowd out intrinsic motivation, inhibiting the very behavior one could try to incentivize. Moreover, human behavior are governed mostly by what is called System 1 – automatic and context-dependent actions that result from learned repertoires and repetition of behaviors over time (Evans, 2009; Kahneman, 2003). The System 1 is evolutionary adaptive inasmuch as it is wired to save cognitive effort. In other words, humans run on automatic pilot most of their time. Thus, the solution to the problem in consideration has to do with a way to signal progress toward goals, a way to impart and increase meaning to donors, all without requiring too much effort from them to keep scores, carry cards or remember when to enact the target behavior.

The solution I propose is twofold: first, to create virtual cards that represent different levels of donation behavior. Second, to attach a symbolic and figurative blood drops to be added after each donation. An e-mail would be sent to the donor after each donation in order to access their personal card online and to share them with friends on virtual communities like Facebook or even on created communities of blood donors. Another e-mail would be sent as a predetermined amount of time has lapsed in order to remind the potential donor that there is a new opportunity to donate. As each donor can go through dozens of rounds of donations over their lives, the cards approach probably would require a “badge” perspective. For instance, an initial donor could complete her first card (named “friend of blood”, for instance) with ten blood figurative drops and then move to another virtual card (let’s call it the “super blood” card) and so on. After each completed card, a donor would receive a letter from the head of agency in charge of blood management demonstrating how many lives he had saved with her behavior thereby adding an additional layer of meaning to the program. The change of level would also be promoted on the relevant virtual communities, to strengthen the new facet of the donor’s identity. Of course this approach could also be used with traditional and constant donors. Above all, it should be tested in an experimental way, using a pilot and a design with a control group, avoiding overconfidence when it concerns us (the program designers) and allowing corrections while maintaining the costs low.




Ariely, D., Bracha, A., & Meier, S. (2009). Doing Good or Doing Well? Image Motivation and Monetary Incentives in Behaving Prosocially. The American Economic Review, 99(1), 544-555.

Bénabou, R. and Tirole, J. (2006). Incentives and prosocial behavior. The American Economic Review, 96 (5), 1652-1678.

Deci, E. L. and Ryan R.M. (Eds.) (2002). The handbook of self-determination research. University of Rochester Press, Rochester, NY.

Evans, J.St.B.T. (2009). How many dual process theories do we need: One, two or many?. In Evans, J.St.B.T. and Frankish, K. (Eds), In Two Minds: Dual Processes and Beyond. Oxford University Press, Oxford, UK, 1-32.

Gneezy, U., & Rustichini, A. (2000). A Fine is a Price. The Journal of Legal Studies, 29(1), 1-17.

Kahneman, D. (2003). A perspective on judgment and choice: Mapping bounded rationality. The American Psychologist, 58 (9), 697-720.