Correcting the nondetection bias of angle count sampling. Ritter, T., Nothdurft, A., & Saborowski, J. Canadian Journal of Forest Research, 43(January):344–354, 2013.
Correcting the nondetection bias of angle count sampling [pdf]Pdf  doi  abstract   bibtex   
The well-known angle count sampling (ACS) has proved to be an efficient sampling technique and has been applied in forest inventories for many decades. However, ACS assumes total visibility of objects; any violation of this assumption leads to a nondetection bias. We present a novel approach, in which the theory of distance sampling is adapted to traditional ACS to correct for the nondetection bias. Two new estimators were developed based on expanding design-based inclusion probabilities by model-based estimates of the detection probabilities. The new estimators were evaluated in a simulation study as well as in a real forest inventory. It is shown that the nondetection bias of the traditional estimator is up to −52.5%, whereas the new estimators are approximately unbiased

Downloads: 0