By Zsóka Vásárhelyi, Barbara Barta, Marianna Biró, Zoltán Csabai, Gábor Földvári, Bálint Halpern, Zsófia Horváth, Erika Juhász, Balázs Károlyi, Kornélia Kurucz, Zsuzsanna Márton, László Mezőfi, Péter Lovászi, Barna Páll-Gergely, Bálint Pernecker, Ádám Selmeczi-Kovács, Zoltán Soltész, Éva Szabó, Ágnes Turóci, Vadonleső Group, Judit Vörös, and László Zsolt Garamszegi.

Wildflowers above Lake Balaton, Hungary – landscapes like these are often where citizen science observations take place. Photo: Zsóka Vásárhelyi

This Plain Language Summary is published in advance of the paper discussed. Please check back soon for a link to the full paper.

Citizen science projects are efforts to gather scientific information by enlisting individuals who are not scientists to help gather data. While these projects receive millions of observations from volunteers around the world, the data collected in ecology and conservation focused projects are often not evenly distributed geographically.

Are the study objects, e.g. certain species, also distributed so unevenly or is this caused by bias? We examined how the environment or characteristics of local human populations influence the number of observations coming from given areas. Seventeen citizen science projects collaborated in this work, covering the entire area of Hungary. By jointly analysing our dataset together with official regional statistics, we found that municipalities with fewer people and more protected natural areas tended to produce more citizen science observations. Outside the capital, Budapest, higher levels of education and a larger share of elderly residents were also linked to more observations.

Our findings thus support the idea that most citizen science datasets are arguably biased. While some general trends appeared, contextuality also emerged as a major factor in the nature of this bias. Our work may improve future project designs and support more careful analysis and interpretation of citizen science data.