Doctoral Student

Carmen Wang

Journal Articles

  1. The Market for Blood

    Robert Slonim, Carmen Wang and Ellen Garbarino

    Donating blood, "the gift of life," is among the noblest activities and it is performed worldwide nearly 100 million times annually. The economic perspective presented here shows how the gift of life, albeit noble and often motivated by altruism, is heavily influenced by standard economic forces including supply and demand, economies of scale, and moral hazard. These forces, shaped by technological advances, have driven the evolution of blood donation markets from thin one-to-one "marriage markets" in which each recipient needed a personal blood donor, to thick, impersonalized, diffuse markets. Today, imbalances between aggregate supply and demand are a major challenge in blood markets, including excess supply after disasters and insufficient supply at other times. These imbalances are not unexpected given that the blood market operates without market prices and with limited storage length (about six weeks) for whole blood. Yet shifting to a system of paying blood donors seems a practical impossibility given attitudes toward paying blood donors and concerns that a paid system could compromise blood safety. Nonetheless, we believe that an economic perspective offers promising directions to increase supply and improve the supply and demand balance even in the presence of volunteer supply and with the absence of market prices.

    Keywords: market design; altruism; philanthropy; Analysis of Health Care Markets; Market Design; Giving and Philanthropy; Health;


    Slonim, Robert, Carmen Wang, and Ellen Garbarino. "The Market for Blood." Journal of Economic Perspectives 28, no. 2 (Spring 2014): 177–196. View Details
  2. Opting-in: Participation Bias in Economic Experiments

    Robert Slonim, Carmen Wang, Ellen Garbarino and Danielle Merrett

    Assuming individuals rationally decide whether to participate or not to participate in lab experiments, we hypothesize several non-representative biases in the characteristics of lab participants. We test the hypotheses by first collecting survey and experimental data from a typical recruitment population and then inviting them to participate in a lab experiment. The results indicate that lab participants are not representative of the target population on almost all the hypothesized characteristics, including having lower income, working fewer hours, volunteering more often, and exhibiting behaviors correlated with interest in experiments and economics. The results reinforce the commonly understood limits of laboratory research to make quantitative inferences. We also discuss several methods for addressing non-representative biases to advance laboratory methods for improving quantitative inferences and consequently increasing confidence in qualitative conclusions.

    Keywords: Participation bias; Laboratory experiments; Prejudice and Bias; Research;


    Slonim, Robert, Carmen Wang, Ellen Garbarino, and Danielle Merrett. "Opting-in: Participation Bias in Economic Experiments." Journal of Economic Behavior & Organization 90 (June 2013): 43–70. View Details
  3. The Multidimensional Effects of a Small Gift:: Evidence from a Natural Field Experiment

    Ellen Garbarino, Robert Slonim and Carmen Wang

    Using a large natural field experiment, we demonstrate that a small unconditional gift (pen) more than doubled both small (survey) and large (blood donation) responses. We find no evidence that the opportunity for a small response crowded out the larger response; asking participants to also complete a survey directionally increased donations.

    Keywords: reciprocity; Gift exchange; Blood donation; Charitable behavior; field experiment; Behavior; Giving and Philanthropy;


    Garbarino, Ellen, Robert Slonim, and Carmen Wang. "The Multidimensional Effects of a Small Gift: Evidence from a Natural Field Experiment." Economics Letters 120, no. 1 (July 2013): 83–61. View Details