Preferential sampling provides a formal modeling specification to capture the effect of bias in a set of sampling locations on inference when a geostatistical model is used to explain observed responses at the sampled locations. In particular, it enables modification of spatial prediction adjusted for the bias. Its original presentation in the literature addressed assessment of the presence of such sampling bias while follow on work focused on regression specification to improve spatial interpolation under such bias. All of the work in the literature to date considers the case of a univariate response variable at each location, either continuous or modeled through a latent continuous variable. The contribution here is to extend the notion of preferential sampling to the case of bivariate response at each location. This exposes sampling scenarios where both responses are observed at a given location as well as scenarios where, for some locations, only one of the responses is recorded. That is, there may be different sampling bias for one response than for the other. It leads to assessing the impact of such bias on co-kriging. It also exposes the possibility that preferential sampling can bias inference regarding dependence between responses at a location. We develop the idea of bivariate preferential sampling through various model specifications and illustrate the effect of these specifications on prediction and dependence behavior. We do this both through simulation examples as well as with a forestry dataset that provides mean diameter at breast height (MDBH) and trees per hectare (TPH) as the point-referenced bivariate responses.
On Ignorability of Preferential Sampling in Geostatistics
Centrum Wiskunde & Informatica(荷兰数学与计算机科学研究中心);University of Miami(迈阿密大学);Academia Sinica(中央研究院);The Chinese University of Hong Kong, Shenzhen(香港中文大学(深圳))
Accounting for Preferential Sampling Using a Constructed Covariate
Centre of Mathematics of the University of Minho (CMAT)(米尼奥大学数学中心);Department of Mathematics of the Nova School of Science and Technology(新大学科学技术学院数学系);Center for Mathematics and Applications (NOVA Math)(数学与应用研究中心);NOVA University of Lisbon, Caparica, Portugal(里斯本新大学);Portuguese Institute for Sea and Atmosphere (IPMA)(葡萄牙海洋与大气研究所);Center of Statistics and its Applications (CEAUL)(统计学及其应用中心);Military Academy Research Center - Military University Institute (CINAMIL)(军事学院研究中心);Engineering Superior Institute of Lisbon (ISEL), Polytechnic Institute of Lisbon(里斯本高等工程学院);NOVA University of Lisbon, Portugal(里斯本新大学)
Department of Mathematics of the Nova School of Science and Technology(新理工大学数学系);Center for Mathematics and Applications (NOVA Math)(应用数学中心(NOVA Math));NOVA University of Lisbon, Caparica, Portugal(里斯本诺瓦大学);Instituto Politécnico do Cávado e Ave (IPCA)(卡瓦多和阿韦理工学院)