First, I would like to note that I’m not a practical communication specialist and our goal was to map the social media environment and not test specific campaigns/appropriateness for social media platform, so take my advice with a grain of salt.

Simplified: we found more personal topics on Facebook, and more general (discussion) topics on Twitter. Our more general recruitment campaigns (e.g., campaigns focussing on missing blood types, and blood saves lives) were found mostly on Twitter. My key advice would be to use Twitter for campaigns that do not have a personal focus most appropriate for key demographics such as family and friends (more likely to be found at symmetrical networks such as Facebook). Not something with the aim of social contagion behavior (e.g., donors sharing that they donated). Twitter is promising for other campaigns as the asymmetrical nature makes that networks are often larger, and it is easier to spread beyond established relationships. The high prevalence of our more general campaigns found on Twitter support this.

Furthermore, I can share with you two recent successful campaigns/posts at Sanquin as these might provide some additional insights. Both campaigns/posts were successful on Twitter and are in line with the topics differences we find on asymmetrical and symmetrical networks. We conducted a campaign (#MyFirstBlood) aimed at gamers using the popular esports-game League of Legends. People who came in for a first appointment received a free piece of game content. Another campaign/post was highly shared during the early covid era, when blood shortage (due to covid) was announced, and donors were asked to come donate (see our recent article for more information on this: https://doi.org/10.1111/trf.16334).

Both these campaigns provide you with something (e.g., value in the #MyFirstBlood campaigns, and urgent need in case of the Covid posts) that you can easily share with your network that does not necessary consist of closer relationships (i.e., family and friends).

Lastly, I would like to note that research by Abassi et al. (2018) (https://doi.org/10.1016/j.tele.2017.01.010) shows that Twitter can also be a promising tool for personal blood donation requests and dissemination (urgent need again).

I think that social security and inequality may indeed shape norms about providing incentives. We did not look into these two macro level factors specifically, but we do think that attitudes about incentives are shaped by various factors (including historical, cultural and economic ones). For example, one factor that we discuss also in the paper as a possible explanation for why norms regarding incentives vary is (post-) materialism. That is, countries that are in earlier stages of economic development and have more economic scarcity may be more concerned with materialist goals than non-materialist goals such as self-expression or autonomy. Economic development is then again related to how well societies can provide social security to its members. In general, the question of where these attitudes come from is extremely interesting, and researchers from many disciplines have explored this question. I would definitely be excited to be able to look into such factors in the future.

The extra information took the form of a brochure that contained the following elements:

– some general information about the usefulness of deferral policies to protect both donors and recipients

– some information about the most common reasons for deferral (low haemoglobin and travel-related infections)

– information about the option to do an online self-check to (hopefully) prevent future deferrals

– statement that the donor will receive a new invitation once they’re eligible again and their blood type is in demand, and that their return will be much appreciated

– Contact information for the donor information call centre in case of further questions.

With regard to the completion of alternative good deeds, we do not have the exact numbers as we didn’t track whether donors actually performed the alternative offered to them. We do however have a rough indication in the form of the number of questionnaires and cards that were returned, which was at around 252 questionnaires and 162 cards. To provide some context, we know that at least 176 donors were assigned to the questionnaire condition and at least 39 donors chose to fill out the questionnaire in the choice-condition, so more questionnaires were returned than one would expect. Similarly high number were seen for the cards, so we assume that the majority of donors did actually perform the offered alternative (plus some donors probably wanted in on the fun while they weren’t deferred).