Value of citizen observations with respect to in-situ monitoring networks

Citizen Science (CS) projects structured for the purpose of data collection are proliferating in the last decade, with a common believe that it could be more cost effective than traditional environmental monitoring networks. However, there are few studies that confirm this claim. In this work, a methodology to evaluate the impact of data coming from CS projects, with respect to the existing in-situ network is developed. The methodology combines a cost-benefit approach with a complementarity approach with respect to existing monitoring networks, and it consists of two main parts, namely the data perspective and the costs perspective. The former aims to qualify the degree of complementarity that the data collected by citizens offers to in-situ networks in terms of space and time, based on the scales of the observed variables. The latter aims to qualify the relation between the investments required to set up a citizen observatory, including stakeholder engagement activities and training, and the actual amount of data collected. We introduce the notion of the Cost of Data Record (CDR), which is to be considered of maximum value if its complementarity is the maximum and if the cost to produce it is the minimum. On the contrary, CDR has little value if its complementarity is the minimum and its cost is high. Results show that building a CO for the only purpose of data collection is an expensive undertaking that do not necessarily complement the existing in-situ monitoring system, and that campaign-based approaches are more effective to this end.