Urban Crowdsourcing Platforms across the World: A Systematic Review.

Urban crowdsourcing platforms are becoming increasingly important, especially considering the relevance of citizen-centricity in smart cities. This systematic review aims at analyzing existing academic literature on urban crowdsourcing platforms to gather citizen-generated data and shed light on the state of research and development of these tools. Studies describing data-gathering urban crowdsourcing platforms were selected following the PRISMA protocol, for a total of 30 studies, corresponding to 32 platforms. After analyzing the studies at large, this review then proceeds to examine and catalogue the platforms, focusing on their location, purpose, and public data availability. While providing valuable information on existing platforms, the catalogue is subject to different types of bias, including a geographical one, which derive primarily from the chosen methodology to identify platforms worldwide. The article also discusses the implications of such choices.