Conventional science is usually conducted in a remote location, abstracted from day-to-day conditions and needs. Even when it produces useful outputs, those outputs are rarely effectively communicated to those who could put them to best use. “Citizen science” is increasingly providing powerful alternatives to this approach.

Though citizen science often evokes images of, for example, school children measuring rainfall, we see it as a much larger field. Citizen science can range from crowd-sourcing information to participatory monitoring and action research, to collaboration between the general public and professional scientists, and to highly informed public science interests funded by citizens.

The common threads of citizen science are:

1. Citizen science functions as a check and balance on information. In places where information is controlled by governments or the private sector and there is limited access or manipulation, citizen science can increase access to information or provide alternative information.

2. Citizen science operates at different scales. It is often granular and/or collected by hundreds or thousands of people and can, therefore, provide very different information from what is available through conventional channels, allowing for investigations that have not previously been possible.

3. Citizen science is grounded locally and relates to issues that people see and/or experience on a daily basis. This relevancy aids in community ownership of the results and makes them more actionable.

4. Citizen science cultivates an informed and engaged citizenship. Participants understand the value of science and see themselves as an integral part of that science. Ideally, this translates to a more informed public and greater citizen engagement in influencing science-policy decisions.

These differences between citizen science and conventional science mean that citizen science can generate unexpected – and sometimes very different – knowledge. That knowledge can lead to transformative change in how processes are undertaken and in how people act.

Citizen science is supporting the growth of new scientific endeavors in powerful ways, particularly as technology has progressed and virtual networks have expanded, increasing scientific literacy and inclusivity (Bonney et al. 2009; Connors et al. 2012). Yet, it is not clear that citizen science is being used to its fullest potential. Indeed, Mueller and Tippins (2012: 3) argue that citizen science has largely been top-down:

The key point is that it does not matter whether or not individuals engage in citizen science projects focused on mammals, birds, weather, climate change, flora, or invasive species. The participants primarily serve to collect data for scientists rather than to collaborate with scientists, democratize protocol and equipment, assess ideas, and work in relation to others.

For this reason, we are encouraged to see the emergence of a new type of citizen science, one based on equitable collaboration. In this citizen science, citizens are engaged as equal players in the scientific process, contributing their local, grounded perspectives, knowledges, understandings, needs, and aspirations in an ongoing and iterative process. This is related to but different from action research, which is either initiated by researchers to solve an immediate problem or is an iterative learning and doing process. Action research doesn’t necessarily engage citizens. Citizen science empowers citizens to act, and makes science directly responsive to their needs and interests. Therefore, citizen science is especially important for urban-focused science, in which a multitude of diverse perspectives and knowledges need to be captured. This chapter explores several case studies from urban areas in which citizens were engaged in equitable collaboration, and how this led to new learning and action.