<p>Data contributed by citizen scientists raise increasing interest in many areas of scientific research. Increasingly, projects rely on information technology such as mobile applications (apps) to facilitate data collection activities by lay people. When developing such smartphone apps, it is essential to account for both the requirements of the scientists interested in acquiring data and the needs of the citizen scientists contributing data. Citizens and participating scientists should therefore ideally work together during the conception, design and testing of mobile applications used in a citizen science project. This will benefit both sides, as both scientists and citizens can bring in their expectations, desires, knowledge, and commitment early on, thereby making better use of the potential of citizen science. Such processes of app co-design are highly transdisciplinary, and thus pose challenges in terms of the diversity of interests, skills, and background knowledge involved.</p><p>Our &#8220;Nachtlicht-B&#252;HNE&#8221; citizen science project addresses these issues. Its major goal is the development of a co-design process enabling scientists and citizens to jointly develop citizen science projects based on smartphone apps. This includes (1) the conception and development of a mobile application for a specific scientific purpose, (2) the design, planning and organization of field campaigns using the mobile application, and (3) the evaluation of the approach. In Nachtlicht-B&#252;HNE, the co-design approach is developed within the scope of two parallel pilot studies in the environmental and space sciences. Case study 1 deals with the problem of light pollution. Currently, little is known about how much different light source types contribute to emissions from Earth. Within the project, citizens and researchers will develop and use an app to capture information about all types of light sources visible from public streets. Case study 2 focuses on meteors. They are of great scientific interest because their pathways and traces of light can be used to derive dynamic and physical properties of comets and asteroids. Since the surveillance of the sky with cameras is usually incomplete, reports of fireball sightings are important. Within the project, citizens and scientists will create and use the first German-language app that allows reporting meteor sightings.</p><p>We will share our experiences on how researchers and communities of citizen scientists with backgrounds in the geosciences, space research, the social sciences, computer science and other disciplines work together in the Nachtlicht-B&#252;HNE project to co-design mobile applications. We highlight challenges that arose and present different strategies for co-design that evolved within the project accounting for the specific needs and interests of the communities involved.</p>
Evaluating consumer food safety mobile applications: lessons learned from combining assessment of users, usability and context