1. A method of determining a measure of likelihood that a designated wireless device exhibits at least one pathological characteristic, the pathological characteristic causing errors in position estimation to occur when the designated wireless device is used as a landmark in a position estimation system if left uncorrected, the method comprising: determining a set of one or more reference points associated with a designated wireless device, one or more of the reference points being at least one of (i) a geographic position at which signals from the designated wireless device were detected and (ii) another wireless device from which signals were also detected by a receiver within a selected period of time during which the signals from the designated wireless device were detected by the receiver; retrieving at least one of (i) attributes of the reference points of the set, (ii) attributes associated with the reception of signals from the designated wireless device and the another wireless device within the selected period of time, and (iii) statistical information about at least one of: a temporal distribution of times of detection of signals of reference points of the set, a spatial distribution of the reference points, and a cardinality of the set or at least one subset of the reference points; and determining a measure of likelihood that the designated wireless device exhibits at least one pathological characteristic based on at least one of (i) attributes of the reference points, (ii) attributes associated with the reception of signals, and (iii) the statistical information.