Classification of Citizen Science activities

As part of the Volunteered Geographic Information (VGI) workshop that was held in Seattle in April 2011, Daniel Sui, Sarah Elwood and Mike Goodchild announced that they will be editing a volume dedicated to the topic, published as ‘Crowdsourcing Geographic Knowledge‘  (Here is a link to the Chapter in Crowdsourcing Geographic Knowledge)

My contribution to this volume focuses on citizen science, and shows the links between it and VGI. The chapter is currently under review, but the following excerpt discusses different types of citizen science activities, and I would welcome comments:

“While the aim here is not to provide a precise definition of citizen science. Yet, a definition and clarification of what the core characteristics of citizen science are is unavoidable. Therefore, it is defined as scientific activities in which non-professional scientists volunteer to participate in data collection, analysis and dissemination of a scientific project (Cohn 2008; Silvertown 2009). People who participate in a scientific study without playing some part in the study itself – for example, volunteering in a medical trial or participating in a social science survey – are not included in this definition.

While it is easy to identify a citizen science project when the aim of the project is the collection of scientific information, as in the recording of the distribution of plant species, there are cases where the definition is less clear-cut. For example, the process of data collection in OpenStreetMap or Google Map Maker is mostly focused on recording verifiable facts about the world that can be observed on the ground. The tools that OpenStreetMap mappers use – such as remotely sensed images, GPS receivers and map editing software – can all be considered scientific tools. With their attempt to locate observed objects and record them on a map accurately, they follow the footsteps of surveyors such as Robert Hooke, who also carried out an extensive survey of London using scientific methods – although, unlike OpenStreetMap volunteers, he was paid for his effort. Finally, cases where facts are collected in a participatory mapping activity, such as the one that Ghose (2001) describes, should probably be considered a citizen science only if the participants decided to frame it as such. For the purpose of the discussion here, such a broad definition is more useful than a limiting one that tries to reject certain activities.

Notice also that, by definition, citizen science can only exist in a world in which science is socially constructed as the preserve of professional scientists in academic institutions and industry, because, otherwise, any person who is involved in a scientific project would simply be considered a contributor and potentially a scientist. As Silvertown (2009) noted, until the late 19th century, science was mainly developed by people who had additional sources of employment that allowed them to spend time on data collection and analysis. Famously, Charles Darwin joined the Beagle voyage, not as a professional naturalist but as a companion to Captain FitzRoy. Thus, in that era, almost all science was citizen science albeit mostly by affluent gentlemen scientists and gentlewomen. While the first professional scientist is likely to be Robert Hooke, who was paid to work on scientific studies in the 17th century, the major growth in the professionalisation of scientists was mostly in the latter part of the 19th and throughout the 20th centuries.

Even with the rise of the professional scientist, the role of volunteers has not disappeared, especially in areas such as archaeology, where it is common for enthusiasts to join excavations, or in natural science and ecology, where they collect and send samples and observations to national repositories. These activities include the Christmas Bird Watch that has been ongoing since 1900 and the British Trust for Ornithology Survey, which has collected over 31 million records since its establishment in 1932 (Silvertown 2009). Astronomy is another area where amateurs and volunteers have been on par with professionals when observation of the night sky and the identification of galaxies, comets and asteroids are considered (BBC 2006). Finally, meteorological observations have also relied on volunteers since the early start of systematic measurements of temperature, precipitation or extreme weather events (WMO 2001).

This type of citizen science provides the first type of ‘classic’ citizen science – the ‘persistence’ parts of science where the resources, geographical spread and the nature of the problem mean that volunteers sometimes predate the professionalisation and mechanisation of science. These research areas usually require a large but sparse network of observers who carry out their work as part of a hobby or leisure activity. This type of citizen science has flourished in specific enclaves of scientific practice, and the progressive development of modern communication tools has made the process of collating the results from the participants easier and cheaper, while inherently keeping many of the characteristics of data collection processes close to their origins.

A second set of citizen science activities is environmental management and, even more specifically, within the context of environmental justice campaigns. Modern environmental management includes strong technocratic and science oriented management practices (Bryant & Wilson 1998; Scott & Barnett 2009) and environmental decision making is heavily based on scientific environmental information. As a result, when an environmental conflict emerges – such as a community protest over a local noisy factory or planned expansion of an airport – the valid evidence needs to be based on scientific data collection. This aspect of environmental justice struggle is encouraging communities to carry out ‘community science’ in which scientific measurements and analysis are carried out by members of local communities so they can develop an evidence base and set out action plans to deal with problems in their area. A successful example of such an approach is the ‘Global Community Monitor’ method to allow communities to deal with air pollution issues (Scott & Barnett 2009). This is performed through a simple method of sampling air using plastic buckets followed by analysis in an air pollution laboratory, and, finally, the community being provided with instructions on how to understand the results. This activity is termed ‘Bucket Brigade’ and was used across the world in environmental justice campaigns. In London, community science was used to collect noise readings in two communities that are impacted by airport and industrial activities. The outputs were effective in bringing environmental problems to the policy arena (Haklay, Francis & Whitaker 2008). As in ‘classic’ citizen science, the growth in electronic communication has enabled communities to identify potential methods – e.g. through the ‘Global Community Monitor’ website – as well as find international standards , regulations and scientific papers that can be used together with the local evidence.
However, the emergence of the Internet and the Web as a global infrastructure has enabled a new incarnation of citizen science: the realisation of scientists that the public can provide free labour, skills, computing power and even funding, and, the growing demands from research funders for public engagement all contributing to the motivation of scientists to develop and launch new and innovative projects (Silvertown 2009; Cohn 2008). These projects utilise the abilities of personal computers, GPS receivers and mobile phones to double as scientific instruments.

This third type of citizen science has been termed ‘citizen cyberscience’ by Francois Grey (2009). Within it, it is possible to identify three sub-categories: volunteered computing, volunteered thinking and participatory sensing.

Volunteered computing was first developed in 1999, with the foundation of SETI@home (Anderson et al. 2002), which was designed to distribute the analysis of data that was collected from a radio telescope in the search for extra-terrestrial intelligence. The project utilises the unused processing capacity that exists in personal computers, and uses the Internet to send and receive ‘work packages’ that are analysed automatically and sent back to the main server. Over 3.83 million downloads were registered on the project’s website by July 2002. The system on which SETI@home is based, the Berkeley Open Infrastructure for Network Computing (BOINC), is now used for over 100 projects, covering Physics, processing data from the Large Hadron Collider through LHC@home; Climate Science with the running of climate models in; and Biology in which the shape of proteins is calculated in Rosetta@home.

While volunteered computing requires very little from the participants, apart from installing software on their computers, in volunteered thinking the volunteers are engaged at a more active and cognitive level (Grey 2009). In these projects, the participants are asked to use a website in which information or an image is presented to them. When they register onto the system, they are trained in the task of classifying the information. After the training, they are exposed to information that has not been analysed, and are asked to carry out classification work. Stardust@home (Westphal et al. 2006) in which volunteers were asked to use a virtual microscope to try to identify traces of interstellar dust was one of the first projects in this area, together with the NASA ClickWorkers that focused on the classification of craters on Mars. Galaxy Zoo (Lintott et al. 2008), a project in which volunteers classify galaxies, is now one of the most developed ones, with over 100,000 participants and with a range of applications that are included in the wider Zooniverse set of projects (see .

Participatory sensing is the final and most recent type of citizen science activity. Here, the capabilities of mobile phones are used to sense the environment. Some mobile phones have up to nine sensors integrated into them, including different transceivers (mobile network, WiFi, Bluetooth), FM and GPS receivers, camera, accelerometer, digital compass and microphone. In addition, they can link to external sensors. These capabilities are increasingly used in citizen science projects, such as Mappiness in which participants are asked to provide behavioural information (feeling of happiness) while the phone records their location to allow the linkage of different locations to wellbeing (MacKerron 2011). Other activities include the sensing of air-quality (Cuff 2007) or noise levels (Maisonneuve et al. 2010) by using the mobile phone’s location and the readings from the microphone.”

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Professor of GIScience, University College London

9 thoughts on “Classification of Citizen Science activities”

  1. Nicolas Maisonneuve alerted me to several other classifications that are available – Wiggins and Crowston “Goals and Tasks: Two Typologies of Citizen Science Projects”.

    In addition, this Wigins and Crowston paper mentions the following:

    C. B. Cooper, J. Dickinson, T. Phillips, and R. Bonney, “Citizen Science as a Tool for Conservation in Residential Ecosystems,” Ecology and Society, vol. 12, no. 2, 2007.

    C. C. Wilderman, “Models of community science: design lessons from the field,” in Citizen Science Toolkit Conference, C. McEver, R. Bonney, J. Dickinson, S. Kelling, K. Rosenberg, and J. L. Shirk, Eds., Cornell Laboratory of Ornithology, Ithaca, NY, 2007.

    A. Wiggins and K. Crowston, “From conservation to Crowdsourcing: A typology of citizen science,” in Proceedings of the Forty-fourth Hawai’i International Conference on System Science (HICSS-44), Koloa, HI, 1/2011 2011.

  2. Very interesting post. I’ve been looking at the same issue of defining Citizen Science (from more of a user perspective) and found this helpful in refining my own thoughts. One thought I had was that it’s not just non-professional scientists who are involved, but also professionals who are working in areas ourside their own disciplines. They are sometimes the most avid and can provide “near-professional” level work for citizen science projects.

    I also thought it goes beyond just volunteering. Various challenge projects have currently shown success, and I think there are many ways the field can go to provide financial support to individuals through science while maintaining the “citizen” in citizen science.

    Feel free to read more about it on my OpenScientist blog site ( or individual posts (such as and

    I’d also be curious to hear your thoughts.

    1. Your exploration and definition of citizen science are very interesting.

      Notice that in my post I deliberately stated that I don’t think that clear cut or very specific definitions are necessary. This is because we are at the beginning of a new acceptance of citizen science as a legitimate form of involvement and engagement in the scientific endeavour. If we try to close the definitions in this stage on the basis of current observations, we might miss some important activities. At you’ve noted on your blog, for me it is important that citizen scientist can participate in all the aspects of the activity – including dissemination. This does happen in some areas already – for example, in Astronomy, it is accepted that amateurs identify asteroids and name them. So I am for more inclusive definitions.

      Having said that, I do like your definition of citizen science and scientists. I do see some problem in it, as your definition of citizen science actually excludes vocational researchers – so maybe update it to:

      Citizen Science: The systematic collection and analysis of data; development of technology; testing of natural phenomena; and the dissemination of these activities by researchers where the majority of the activities are on an avocational basis.

  3. Good point. I’ve actually made the change you recommended too focus on “primarily” avocational researchers. It’s good to include this group that may be working on problems from both sides of the “professional” divide.

  4. I’m looking at citizen science, especially in the realm of conservation biology. Several other authors have attempted classifications of citizen science in this area, including Silvertown 2009 “A new dawn for citizen science” and Devictor et al 2010 “Beyond scarcity: citizen science programmes as useful tools for conservation biogeography”. Silvertown differentiates between hypothesis-driven projects, mapping and monitoring projects, and sites with tools. Devictor breaks it down by ecological characteristic. In both cases its easy to find examples of sites falling into more than one class – Devictor lists several examples in two of his three classes for instance.

    Other ways to classify that are also of interest are:
    – temporal scale: ongoing (like Christmas Bird Count) or short-term (like BC Breeding Bird Atlas)
    – accessible data (CBC will share via a request) vs inaccessible data (not clear if Canada’s NatureWatch data can be accessed).

    Another interesting part of the citizen science definition / purpose is to prepare citizens for an increased role in decision-making. I’ve found this in a couple of documents prepared by government agencies in Canada (i.e the manual for ShoreKeepers prepared by the Department of Fisheries and Oceans). These “experts” see involvement in citizen science as a prerequisite for involvement in public participation in conservation planning and management.

    1. Silvertown papers is indeed very good – though they are focused on ecological and biological studies – and I agree that there are many ways to create typologies. What I am trying to do here is to provide an overview for someone new to the field (that’s, after all, the purpose of the chapter). Of course, the concept of ‘extreme citizen science’ that I’m offering argues that citizens can set the research context, do the data collection, analyse the information and decide on a course of action. In the context of planning, the SuScit project (Citizen Science for Sustainability – demonstrated some of this potential.

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