Table 3 Crowdfunding: basic principles

Crowdfunding can be either reward-based, equity-based or donation-based depending on the return that is offered to the funders [45]. Donation-based crowdfunding is most relevant to fund independent clinical research where financial ROI and other rewards are lacking. A donation-based crowdfunding model typically involves three types of stakeholders: the project initiator (in this case a research organisation seeking funding to conduct a clinical trial), the donors, and the online platform provider. Campaigns to fund clinical research can either be hosted on general-purpose (e.g. Indiegogo.com, Kickstarter.com) or research-focused crowdfunding platforms (e.g. Experiment.com, Consano.org). Each campaign features a description of the research project in lay language, a financial goal, and an indication of how close the campaign is to meeting this goal. Most campaigns specify a limited period to accept contributions. Some campaigns adhere to an ‘all-or-nothing’ or ‘fixed-funding’ model, meaning that donations are kept only if the financial goal is met or exceeded.