It seems that the probes may overlap heavily within a given PSR, how is this managed?
In many cases the probes do overlap quite heavily. Multiple probes, although overlapping, are utilized as they still provide separate physical measures of expression and add to the robustness of the platform. Care was taken to ensure that probes from the same probe set, however similar in sequence composition, are spatially separated on the array. In addition, the annotation library file contains information regarding how many independent probes there are, as well as the number of nonoverlapping probes, in each probe set. Independent probes are defined as those that have less or equal to 13 base overlaps with other probes in the probe set. This information provides additional insight and may be helpful to users when interpreting unexpected results.