Citizens can play diverse roles in citizen science projects, ranging from contributing data to actively collaborating with researchers in data analysis, or even participating in disseminating research results. This section delves into effective strategies for engaging citizens at different stages of the project and maximizing the value of their collaboration. Our researchers also share their insights on the impact citizens have had on the quality and outcomes of their projects.

The extent of citizen involvement and their specific roles within a project vary in accordance with the project's objectives. Moreover, distinct groups of citizens may assume diverse roles at different stages of the project, engaging through various modes and bringing their specific perspective.

• Citizens are providers of data: Through different interactive activities citizens gather or produce relevant data.

• Citizens are co-producers of the research question: Citizens provide valuable insights and engage in testing preliminary concepts, allowing the validation or alteration of the initial thesis of the research and ultimately shape the research object.

• Citizens are protagonists of research activities: Citizens' active involvement often stems from the acknowledgment that they will ultimately serve as primary beneficiaries of the research findings, so their perspective holds paramount importance.

• Citizens are the main target audience of research outcomes: Furthermore, the citizens' experience of consuming or enjoying the project's outcomes can also play a crucial role in evaluating the project's success.

• Citizens are promoters of the project: Citizens are those who make the project visible and extend its outreach beyond the academic community.

It is important to know that even when the activities of citizens are limited to providing data, their role in the project is never minor. Citizen science brings unique opportunities to gather data that otherwise would not be accessible for the researcher. Citizen science can also be a method for processing large amounts of data which require analysis by a human being.

The data provided by citizens have its particular characteristics that must be taken into consideration to avoid biases regarding the data quality. Data reliability and its possible interpolation with other types of quantitative data should, therefore, be considered when designing the data architecture for the project.

It is essential to comprehend how the data is generated and to recognize what type of phenomenon it contributes to highlighting. Data collected from citizens has the potential to challenge and reshape the conventional perspective of the academic science.