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. 2019 Feb 4;116(6):1894–1901. doi: 10.1073/pnas.1807186115

Fig. 1.

Fig. 1.

The retention landscape in active citizen science. (A) Retention in the COASST program measured as the duration between first and last survey date for all participants (red; n = 2,511) and for regular participants only (i.e., subtracting guests; blue; n = 1,654). Points along the curve (left to right) indicate time points following the first survey, at 1 y, and at 5 y. (B) Results of a meta-analysis of 54 citizen science projects reporting one or both of the percentage of the contributing population interacting for only a single session, observation, task, or survey (i.e., dabblers; n = 41) and the percentage of the contributing population remaining active in the project past 1 y (n = 39). Projects with total turnover at 1 y are in the bar below zero. Histograms are binned counts of all projects for which the relevant data were obtainable; scatterplot points represent projects for which both metrics were available (n = 26). Projects were a priori categorized into four exclusive classes. Stars represent the COASST project (black outline, all participants; red outline, regular participants only). SI Appendix, Table S1 provides a list of projects and sources.