Abstract
Citizen science projects need to attract citizens and motivate them to dedicate their energy and time to science. Recruiting enough participants and keeping them engaged throughout the project is often a big challenge for the scientists involved. In this paper, recruiting and engagement strategies are evaluated for a successful midsize online citizen science project in the field of humanities. Quantitative measures are applied to track the quantity and quality of citizens’ contributions over time, allowing understanding of the dynamics of engagement in citizen science. The study shows that monitoring the level of activity and the quality of contributions provides useful insights about a project’s dynamics. We found that a small core group of volunteers was responsible for most of the input to the project, that their transcriptions were very accurate from the start, and that prompt feedback on their performance was important to keep activity levels high.