Citizen science is promoted as a simple and cost-effective alternative to traditional approaches for the monitoring of populations of marine megafauna. However, the reliability of datasets collected by these initiatives often remains poorly quantified. We compared datasets of shark counts collected by professional dive guides with acoustic telemetry data from tagged sharks collected at the same coral reef sites over a period of five years. (PLoS One, April 23, 2014)

Citizen science may be especially effective in urban landscapes due to the large pool of potential volunteers. However, there have been few evaluations of the contributions of citizen scientists to knowledge of biological communities in and around cities. To assess the effectiveness of citizen scientists' monitoring of species in urban areas, we compared butterfly data collected over 10 years in Chicago, Illinois (U.S.A.), and New York City, New York (U.S.A.). (Conservation Biology 26(3), 557-64 (2012)).

Citizen science is having increasing influence on environmental monitoring as its advantages are becoming recognised. However methodologies are often simplified to make them accessible to citizen scientists. We tested whether a recent citizen science survey (the OPAL Air Survey) could detect trends in lichen community composition over transects away from roads. (Environmental Pollution 182, 448-451 (2013)).

In this paper we present the results of a series of qualitative interviews with scientists who participated in the ‘OPAL’ portfolio of citizen science projects that has been running in England since 2007: What were their experiences of participating in citizen science? While we share the general enthusiasm over citizen science, we hope that the research in this paper opens up more debate over the potential pitfalls of citizen science as seen by the scientists themselves. (Public Understanding of Science, January 2014 23(1), 107-120)

Citizen Science (CS) is a research approach that has become popular in recent years and offers innovative potential for dialect research in ornithology. As the scepticism about CS data is still widespread, we analysed the development of a 3-year CS project based on the song of the Common Nightingale (Luscinia megarhynchos) to share best practices and lessons learned. We focused on the data scope, individual engagement, spatial distribution and species misidentifications from recordings generated before (2018, 2019) and during the COVID-19 outbreak (2020) with a smartphone using the ‘Naturblick’ app. (Journal of Ornithology 164, 233-244 (2023)). [open access]

Full citation: Carroll. C. et al (2025). Citizen Science: Theory and Practice 10(1), 11.

Involving the public in research may provide considerable benefits for the progress of science. However, the sustainability of “crowd science” approaches depends on the degree to which members of the public are interested and provide continued labor inputs. We describe and compare contribution patterns in multiple projects using a range of measures. We show that effort contributions can be significant in magnitude and speed, but we also identify several challenges. In addition, we explore some of the underlying dynamics and mechanisms. As such, we provide quantitative evidence that is useful for scientists who consider adopting crowd science approaches and for scholars studying crowd-based knowledge production. Our results also inform current policy discussions regarding the organization of scientific research. (Proceedings of the National Academy of Sciences, 2015).

Citizen science programs are touted as useful tools for engaging the public in science and for collecting important data for scientists and resource managers. To accomplish the latter, it must be shown that data collected by volunteers is sufficiently accurate and reliable. We engaged 119 volunteers over three years to map and estimate abundance of invasive plants in New York and New Jersey parklands. We tested their accuracy via collected pressed samples and by subsampling their transect points. We also compared the performances of volunteers and botanical experts. Our results support the notion that volunteer participation can enhance the data generated by scientists alone. (Environmental Management 49(2), 425-434 (2912)).

Concerns about pollinator declines have grown in recent years, yet the ability to detect changes in abundance, taxonomic richness, and composition of pollinator communities is hampered severely by the lack of data over space and time. Citizen scientists may be able to extend the spatial and temporal extent of pollinator monitoring programs. We developed a citizen-science monitoring protocol in which we trained 13 citizen scientists to observe and classify floral visitors at the resolution of orders or super families (e.g., bee, wasp, fly) and at finer resolution within bees (superfamily Apoidea) only. We evaluated the protocol by comparing data collected simultaneously at 17 sites by citizen scientists (observational data set) and by professionals (specimen-based data set). (Conservation Biology 25(3), 607-17 (2011)).

Citizen science can aid decision-making to mitigate wildlife/highway conflicts. We audited a highway wildlife-reporting citizen science program. We compared a systematically-derived dataset with the citizen-derived dataset. The datasets showed significant spatial agreement and the citizen data were robust. This and other citizen science programs should record search and reporting effort. (Journal of Environmental Management, Volume 139, 15 June 2014, Pages 180–187).

Citizen scientist programs are a means to efficiently conduct large-scale surveys of ecosystems or managed species, provided that concerns over the quality and use of data generated by nonexperts can be addressed. This study presents actions taken in a citizen science program to assure data quality and demonstrates the validity of citizen-generated data. (Ecological Applications 22(4), 1201-12 (2012)).

An increasingly sophisticated public, rapid changes in monitoring technology, the ability to process large volumes of data, and social media are increasing the capacity for members of the public and advocacy groups to gather, interpret, and exchange environmental data. This development has the potential to alter the government-centric approach to environmental governance; however, citizen science has had a mixed record in influencing government decisions and actions. This Article reviews the rapid changes that are going on in the field of citizen science and examines what makes citizen science initiatives impactful, as well as the barriers to greater impact. It reports on 10 case studies, and evaluates these to provide findings about the state of citizen science and recommendations on what might be done to increase its influence on environmental decision making. (Wyeth, George and Paddock, LeRoy C and Parker, Alison and Glicksman, Robert L. and Williams, Jecoliah, The Impact of Citizen Environmental Science in the United States (March 2019). Environmental Law Reporter, Vol. 49, No. 3, 2019)

Ecologically oriented citizen‐science experiences engage the public in learning while facilitating the achievement of robust scientific program goals. Evaluation of learning outcomes has become increasingly prioritized, requiring citizen‐science program managers to understand key issues in evaluation. We argue that citizen science can have other, more far‐reaching community‐level outcomes, which have received less attention but warrant consideration for continued programmatic improvement. (Frontiers in Ecology and the Environment, 10: 307-309 (2012)).

Citizen-science programs are often touted as useful for advancing conservation literacy, scientific knowledge, and increasing scientific-reasoning skills among the public. Guidelines for collaboration among scientists and the public are lacking and the extent to which these citizen-science initiatives change behavior is relatively unstudied. Over two years, we studied 82 participants in a three-day program that included education about non-native invasive plants and collection of data on the occurrence of those plants...We tested whether participants without experience in plant identification and with little knowledge of invasive plants increased their knowledge of invasive species ecology, participation increased knowledge of scientific methods, and participation affected behavior. (Conservation Biology 25(6), 1148-54 (2011)).

Citizen‐science programs are often touted as useful for advancing conservation literacy, scientific knowledge, and increasing scientific‐reasoning skills among the public. Guidelines for collaboration among scientists and the public are lacking and the extent to which these citizen‐science initiatives change behavior is relatively unstudied. Over two years, we studied 82 participants in a three‐day program that included education about non‐native invasive plants and collection of data on the occurrence of those plants. Volunteers were given background knowledge about invasive plant ecology and trained on a specific protocol for collecting invasive plant data. They then collected data and later gathered as a group to analyze data and discuss responsible environmental behavior with respect to invasive plants. We tested whether participants without experience in plant identification and with little knowledge of invasive plants increased their knowledge of invasive species ecology, participation increased knowledge of scientific methods, and participation affected behavior. Knowledge of invasive plants increased on average 24%, but participation was insufficient to increase understanding of how scientific research is conducted. Participants reported increased ability to recognize invasive plants and increased awareness of effects of invasive plants on the environment, but this translated into little change in behavior regarding invasive plants. Potential conflicts between scientific goals, educational goals, and the motivation of participants must be considered during program design. (Conservation Biology, 25: 1148-1154. (2011)).

Community science programs may improve our ability to monitor world bird populations. We use data from eBird to estimate population trends for 9000 bird species. We compare these trends (increasing, stable or decreasing) with those of BirdLife. Overall, eBird trends were marginally better than expected by chance. Agreement improved for common, temperate and increasing species of Least Concern. (Biological Conservation 248, 108653 (2020)).

Despite the wealth of information emerging from citizen science projects, the practice is not universally accepted as a valid method of scientific investigation. Scientific papers presenting volunteer-collected data sometimes have trouble getting reviewed and are often placed in outreach sections of journals or education tracks of scientific meetings. At the same time, opportunities to use citizen science to achieve positive outcomes for science and society are going unrealized. Here, we offer suggestions for strategic thinking by citizen science practitioners and their scientific peers—and for tactical investment by private funders and government agencies—to help the field reach its full potential. (Science 343(6178), 1436-7 (2014)).

Methods are being developed to capitalize on citizen science data for research and monitoring, but these data are rarely used within established decision-making frameworks of wildlife agencies. Citizen science data are often collected at higher resolution and extent than targeted monitoring programs, and may provide complementary information. Here, we demonstrate that carefully filtered semi-structured citizen science observations, when paired with targeted survey data, can produce ecological predictions at higher resolution and extent than targeted surveys alone, and both datasets can represent complementary aspects of species' ecology. (Journal of Biological Conservation, 270, 109556 (2022)).

Citizen science programs are increasingly popular for a variety of reasons, from public education to new opportunities for data collection. The literature published in scientific journals resulting from these projects represents a particular perspective on the process. These articles often conclude with recommendations for increasing "success". This study compared these recommendations to those elicited during interviews with program coordinators for programs within the United States. From this comparison, success cannot be unilaterally defined and therefore recommendations vary by perspective on success. Program coordinators tended to have more locally-tailored recommendations specific to particular aspects of their program mission. (PLoS One, May 15, 2013).

A typical way to quantify aboveground carbon in forests is to measure tree diameters and use species-specific allometric equations to estimate biomass and carbon stocks. Using "citizen scientists" to collect data that are usually time-consuming and labor-intensive can play a valuable role in ecological research. However, data validation, such as establishing the sampling error in volunteer measurements, is a crucial, but little studied, part of utilizing citizen science data. The aims of this study were to (1) evaluate the quality of tree diameter and height measurements carried out by volunteers compared to expert scientists and (2) estimate how sensitive carbon stock estimates are to these measurement sampling errors. (Ecological Applications 23(4), 936-43 (2013)).

Worldwide, decision-makers and non-government organizations are increasing their use of citizen volunteers to enhance their ability to monitor and manage natural resources, track species at risk, and conserve protected areas. We reviewed the last 10 years of relevant citizen science literature for areas of consensus, divergence, and knowledge gaps. Two major gaps were identified: (1) a need to compare and contrast the success (and the situations that induce success) of CBM programs which present sound evidence of citizen scientists influencing positive environmental changes in the local ecosystems they monitor and (2) more case studies showing use of CBM data by decision-makers or the barriers to linkages and how these might be overcome. (Environmental Monitoring & Assessment 176(1-4), 273-291 (2011)).

Environmental monitoring is essential for assessing the current state of the environment, measuring impacts of environmental pressures and providing evidence to government. Recent UK government announcements have indicated an increased role for 'Big Society' in monitoring. In this paper, we review available literature concerning the use of citizen science for monitoring, present examples of successful volunteer monitoring work and highlight important issues surrounding the use of volunteers. (Environmental Monitoring 13(10), 2687-91 (2011)).

Online citizen science offers a low-cost way to strengthen the infrastructure for scientific research and engage members of the public in science. As the sustainability of online citizen science projects depends on volunteers who contribute their skills, time, and energy, the objective of this study is to investigate effects of motivational factors on the quantity and quality of citizen scientists' contribution. Building on the social movement participation model, findings from a longitudinal empirical study in three different citizen science projects reveal that quantity of contribution is determined by collective motives, norm-oriented motives, reputation, and intrinsic motives. Contribution quality, on the other hand, is positively affected only by collective motives and reputation. We discuss implications for research on the motivation for participation in technology-mediated social participation and for the practice of citizen science. (PLoS One, April 1, 2014).

Species' assessments must frequently be derived from opportunistic observations made by volunteers (i.e., citizen scientists). Interpretation of the resulting data to estimate population trends is plagued with problems, including teasing apart genuine population trends from variations in observation effort. We devised a way to correct for annual variation in effort when estimating trends in occupancy (species distribution) from faunal or floral databases of opportunistic observations. (Conservation Biology 24(5), 1388-97 (2010)).

Exposure assessment has shifted from pollutant monitoring in air, soil, and water toward personal exposure measurements and biomonitoring. This trend along with the paucity of health effect data for many of the pollutants studied raise ethical and scientific challenges for reporting results to study participants. We identify three frameworks for report-back in personal exposure studies: clinical ethics; community-based participatory research; and citizen science 'data judo. (Environmental Health 8(6) (2009)).

Our objective was to evaluate the potential of using iNaturalist-generated observations of urban red foxes and coyotes for cost-effective, customizable data collection to inform urban canid management. (Landscape and Urban Planning 189, 362-371 (2019)).

Authors report that eBird observations match trends in bird species populations measured by U.S. government surveys to within 0.4 percent. (Biological Conservation 221, 151–159 (2018)).

Evidence suggests that the involvement of local people in conservation work increases a project's chances of success. Involving citizen scientists in research, however, raises questions about data quality. As a tool to better assess potential participants for conservation projects, we developed a knowledge gradient, K, along which community members occupy different positions on the basis of their experience with and knowledge of a research subject. This gradient can be used to refine the citizen-science concept and allow researchers to differentiate between community members with expert knowledge and those with little knowledge. (Conservation Biology 25(6), 1195-202 (2011)).

Evaluated the relative accuracy of crater counts by scientists and volunteers and found that minimally trained volunteers as an ensemble can reproduce expert crater counts. (Icarus. v. 234, 109-131 (2014)).