On bias, precision and accuracy in wildlife aerial surveys
Jim Hone
+ Author Affiliations
- Author Affiliations
Institute for Applied Ecology, University of Canberra, Canberra, ACT 2601, Australia. Email: jim.hone@canberra.edu.au
Wildlife Research 35(4) 253-257 https://doi.org/10.1071/WR07144
Submitted: 14 September 2007 Accepted: 17 December 2007 Published: 27 June 2008
Abstract
Bias, precision and accuracy have been studied extensively in wildlife population estimation including aerial surveys. A review of the literature shows that the concepts of bias and precision are used broadly consistently. Aerial survey data from known populations of feral pig carcases and white-tailed deer show that few density estimates are unbiased and precise. Research is needed, however, to clarify how much bias and how much precision are enough for the various types of wildlife management activities. Accuracy is used in two closely related but different ways. One set of definitions of accuracy relates to deviations from the true value (bias) and the second set relates to squared deviations from the true value (bias and precision). The implications are that authors are encouraged to clearly state which definition of accuracy they use, or focus solely on bias and precision.
Acknowledgements
I thank Peter Fleming and John Tracey for the invitation to participate in the aerial survey symposium at the 2006 annual meeting of the Australasian Wildlife Management Society. I thank the University of Canberra for support, and D. Ramsey and D. Pederson for statistical advice. P. Caley, C. Krebs and D. Pederson provided useful comments on a draft manuscript.
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