Completed Projects

Blood donor careers (with Tjeerd Piersma, Eva-Maria Merz & Wim de Kort)

PhD candidate Tjeerd Piersma completed his dissertation, including a systematic literature review, three empirical chapters, and a discussion.

The systematic literature review, ‘Individual, contextual and network characteristics of donors and non-donors’, summarizes research on non-experimental blood donation behavior in the past decade.


The review was published in Blood Transfusion, 15(5): 382-397.

In “Blood Donation across the Life Course: The Influence of Life Events on Donor Lapse” we examined how life events are related to dropping out of the blood donor pool, using two waves of survey data on blood donors in the Netherlands matched to registry data on blood donations (n = 20,560). We found that donors were less likely to continue giving blood after childbirth, losing a job, and starting a job. In contrast, they were more likely to continue giving blood after a family member received a blood transfusion, or after a family member died. Materials here: The paper was published in Journal of Health and Social Behavior

In “Life Events and Donor Lapse Among Blood Donors in Denmark”, a study with registry data (n = 152,887, co-authored with Hjalgrim, Andersen, & Ullum), we investigated the same life events. We found that relationships between life events and blood donor loyalty were in the same direction, though the strength of the associations was weaker in Denmark. Materials here: The paper was published in Vox Sanguinis.


Experiments on crowdfunding (with Claire van Teunenbroek and Bianca Beersma)

PhD candidate Claire van Teunenbroek completed her dissertation, including a systematic literature review, three empirical chapters, and a discussion.

The systematic literature review, ‘Look to others before you leap’, analyzes how social information effects on charitable giving may be explained. VanTeunenbroek_LitReviewThe paper was published in Nonprofit & Voluntary Sector Quarterly.

In a natural field experiment with Voordekunst, an online crowdfunding platform for the arts in the Netherlands, we tested whether social information may increase amounts donated. We found a modest increase. The experiment was preregistered on and has been completed. The paper, the data and materials are posted at the OSF. The paper, titled ‘Follow the crowd’, was published in the Journal of Behavioral Public Administration.

In an online experiment among UK participants recruited through Prolific, we tested to what extent social norms may explain social information effects. The paper is called ‘Others are doing it too’. We again found a modest effect of social information, but social norms did not mediate the effect. The preregistration is posted at the OSF. The paper is on its way in the publication pipeline.


20 Years of Giving in the Netherlands (with Arjen de Wit, Pamala Wiepking, and Suzanne Felix)

How have giving and volunteering practices in the Netherlands changed in the past 20 years? Since the Giving in the Netherlands project started in 1995, 10 biennial surveys have been conducted that quantify the size and composition of philanthropy in the Netherlands. We are now stacking all the data that we have collected into one huge data file to answer the questions that ordinarily go unanswered. Who has been driving the increase in the amount donated in the 1990s? Why has giving not increased after 2001? Which households are giving more as a proportion of their income and wealth?

Results from the research were published in Dutch on April 20, 2017, in a volume in Dutch, called Geven in Nederland 2017: Giften, Legaten, Sponsoring en Vrijwilligerswerk. An English paper was presented at the ERNOP conference in Copenhagen and the ISTR Conference in Amsterdam. The paper is posted at the Open Science Framework.


ITSSOIN: Impact of the Third Sector on Social Innovation
What is the impact of the third sector on social innovation in Europe? This was the key question of the ITSSOIN project, coordinated by the Centre for Social Investment (CSI) at the University of Heidelberg. At the Center for Philanthropic Studies I worked with Arjen de Wit, Dave Verkaik and Danique Karamat Ali on this project.

Our contribution focused on the impact of volunteering on volunteers and society at large (WP3). One of the key findings in this project is that volunteering contributes to well-being, health, and the scope and size of social networks. The effects of volunteering are not very large, but consistently positive. Read more about it here. We are working on a journal article reporting the results in a mega-analysis.

Thus far, the ITSSOIN project has resulted in the following papers:

  1. De Wit, A., Mensink, W., Einarsson, T. & Bekkers, R. (2017). Beyond Service Production: Volunteering for Social Innovation. Nonprofit & Voluntary Sector Quarterly,
  2. Anheier, H.K.; Krlev, G.; Preuss, S.; Mildenberger, G.; Bekkers, R.; Mensink, W.; Bauer, A.; Knapp, M.; Wistow, G.; Hernandez, A, & Adelaja, B., (2014). Social Innovation as Impact of the Third Sector. This report describes the general approach that the project will take to study social innovation.
  3. Anheier, H. K., Krlev, G., Preuss, S., Mildenberger, G., Bekkers, R., Brink Lund, A. (2014). ITSSOIN Hypotheses. This report describes the hypotheses to be tested in the project.
  4. Bekkers, R. & Brink Lund, A. (2014). Perceptions of the Third Sector. This report describes empirical analyses of how Europeans view the third sector.
  5. Bekkers, R. & De Wit, A. (2015). Participation in Volunteering: What helps and Hinders. This report provides a literature review of factors that facilitate and inhibit volunteering.
  6. Bekkers, R. & Verkaik, D. (2015). How to estimate what participation in third sector activities does for participants. This report describes various methodologies to estimate the effect of participation in third sector activities, and specifically volunteering, on health, occupation, and well-being.
  7. De Wit, A., Bekkers, R., Karamat Ali, D., & Verkaik, D. (2015). The Welfare Impact of Participation on Participants. A report on the welfare impacts of volunteering, using longitudinal panel datasets from multiple countries in Europe, primarily the UK, the Netherlands, Germany, and Switzerland.
  8. De Wit, A., Mensink, W., Einarsson, T., & Bekkers, R. (2015). Organisations that Facilitate Volunteering. A report on the influence of third sector organisations on volunteers and the role of social innovation.


EUFORI: EU Study on Foundation Funding for Research and Innovation

How much do foundations in Europe spend on Research and Innovation? How do these foundations operate and view their roles vis-a-vis government and corporate actors? The Center of Philanthropic Studies has coordinated a study on European Foundations supporting Research and Innovation (EUFORI). The study was commissioned by the directorate general Research and Innovation of the European Commission. The bulk of the research is conducted by a network of experts on the 27 EU member states from the European Research Network On Philanthropy ( The study builds on a pilot study called FOREMAP published in 2009 by the  European Foundation Centre. More information on the EUFORI study is available here. In the fall of 2014 I have been working on a comparative analysis of R&I support by foundations throughout the European Union. The study is completed, and the results are available here.