Finding relevant participants and establishing initial contact is often recognized as a significant challenge in citizen science. This section aims to provide solutions and strategies to help you overcome such challenges. You will discover the valuable role that third-party partners can play in recruiting participants. Additionally, you will learn how to organize seamless communication among project stakeholders and which technologies and techniques can be used to facilitate this process.

In the interviews, the experts discussed their approaches and techniques for identifying, initiating contact, and involving citizens in the project. Based on their collective experiences, here are their recommendations to successfully engage citizens:

• Launching Participation through Partnerships

For members of academia, it can be challenging to engage with groups which are either segregated from, or simply not in touch with, the university environment. For this reason, partnering with stakeholders who are already engaging them in initiatives and activities can be a fruitful way of establishing a relationship with citizens that is more likely to be based on trust and to elicit a greater willingness to contribute and to collaborate. These entities can be of different nature and have diverse expertise, for example:

1. Enhancing Engagement Through Local Associations: When the participants reside within the same neighborhood, it can be useful to leverage the existing infrastructure. Local associations can play a pivotal role in connecting with the communities. They also may have competencies to diversify participation, such as organizing social and artistic events.
2. Establishing trust and leveraging knowledge of the local context through local municipal entities: Many municipalities, especially in large and/or complex urban contexts have established local branches which work in closer contact with the community. These include neighborhood councils, neighborhood houses, community houses and even health institutions. These can be great sources of knowledge of the local context and can foster interaction with local groups of citizens.
3. Involving Educational institutions: Forging connections with educational institutions can help to engage a younger audience and provide an opportunity to test the project's pedagogical aspects.

• Leveraging Existing Events

Collaborating with established events and utilizing their communication channels can prove highly advantageous. Engaging with events that naturally attract receptive attendees provides an excellent opportunity to initiate contact.

• Cultivating a Loyal Online Community

Initiating a blog or engaging on social media platforms can provide an interactive channel for communication. By creating content that resonates with the target audience and provides entertainment alongside information, it is possible to cultivate a loyal online community. Researchers, however, should bear in mind that some groups, such as elderly, segregated and vulnerable communities, do not always have access to digital devices or proficiency in using it. In this case, offline communication can be more effective.

• Simplifying Engagement Process

When a straightforward engagement process is in place, participants can independently join the project and encourage others to participate.

• Diversifying Engagement activities

In the process of engaging citizens, researchers employ a variety of methods, including interviews, online questionnaires, workshops, and co-design labs. To foster the involvement, participative activities can extend beyond consultations: citizen science projects might need a pedagogical phase to introduce the research subject, or some more ludic activities to create a comfortable environment for people to freely express their views.

• Ensuring transparent communication of the project structure and objectives

Citizens should be made aware of how the project works and what the objectives are, and not just of the part they are called to contribute to. To avoid instrumentalising the participatory approach, and to solidify trust, updates and communications on the project should be ensured throughout the project duration and beyond, to communicate project results and impact.

• Showing their Contribution Matters

The main goal of all the participative activities is not only to collect data but make participation meaningful for the citizens. It is important to make participants feel that their contributions really matter.