Bias phenomenon in multiple target tracking has been observed for a long ti
me. This paper is devoted to a study of the bias resulting from the miscorr
elation in data association. One result of this paper is a necessary condit
ion for miscorrelation to cause bias. Relying on the necessary condition an
d a model for data association process, techniques are developed to give ge
neral directions for where and how to compensate the bias related to miscor
relation in general tracking algorithms. Case studies on the bias phenomeno
n in two tracking algorithms, i.e., global nearest neighborhood (GNN) and j
oint probabilistic data association (JPDA), are launched as a practice of t
he ideas and results presented in this paper. The outcome of the examples i
llustrates and strongly supports our results. A discussion of several stati
stical issues is given in the end of this paper, in which the behavior for
the bias in GNN and JPDA is studied. (C) 2000 Elsevier Science Ltd. All rig
hts reserved.