Reef Check Australia (RCA) has collected data on benthic composition and cover at > 70 sites along > 1000 km of Australia’s Queensland coast from 2002 to 2015. This paper quantifies the accuracy, precision and power of RCA benthic composition data, to guide its application and interpretation. A simulation study established that the inherent accuracy of the Reef Check point sampling protocol is high (<± 7% error absolute), in the range of estimates of benthic cover from 1% to 50%. A field study at three reef sites indicated that, despite minor observer- and deployment-related biases, the protocol does reliably document moderate ecological changes in coral communities. The error analyses were then used to guide the interpretation of inter-annual variability and long term trends at three study sites in RCA's major 2002–2015 data series for the Queensland coast. Source: Done, T., Roelfsema, C., Harvey, A., Schuller, L., Hill, J., Schläppy, M-L., Lea, A., Bauer-Civiello, A., Loder, J., 2017. Reliability and utility of citizen science reef monitoring data collected by Reef Check Australia, 2002–2015. Marine Pollution Bulletin: Volume 117, Issues 1–2, 15 April 2017, Pages 148–155. https://doi.org/10.1016/j.marpolbul.2017.01.054