Abstract
Engaging and retaining participants present major challenges for citizen science programs, especially those that seek to engage participants across a large region. Periodic messages are a commonly used tactic for reminding citizen science program participants to take a desired action such as collecting observations. In this study, we evaluate the impact of such messages on the accuracy and precision of observations contributed to Nature’s Notebook, a citizen science phenology observing program. To encourage participants in Nature’s Notebook to log the timing of leaf-out and flowering with maximum accuracy and precision, we email observers three days prior to when the events are expected to occur based on forecast models. Unplanned interruptions to the scripts driving these email prompts allowed us to evaluate whether the messages had the intended impacts. The messages significantly improved the precision of observers’ reports of leaf-out by five to eight days and the accuracy by one to two days, though these improvements were present only for participants that opened the messages. Accuracy and precision of reports of bloom were not impacted in the same positive ways. These findings demonstrate the importance of timely messages to prompt action and underscore the impact of the first messages sent in the season—both of which have utility for other citizen science programs. Because these findings emerged opportunistically, we cannot establish that the messages caused the changes in participant behavior. A more rigorous evaluation to determine the impact of messaging on volunteer observer behavior is merited.