An apparatus obtains instances of positioning quality information comprising respective position estimates, respective positioning approach indicators, and respective characteristics of the respective position estimates. The apparatus partitions the instances of positioning quality information into a plurality of groups, where each group corresponds to a geographic area, and partitions the instances of each group into clusters corresponding to positioning approaches. For each respective cluster of each respective group, the apparatus determines a respective positioning index based at least in part on respective characteristics of the respective instances of positioning quality information assigned to the respective cluster. The apparatus provides at least one instance of positioning index information, such that performance of a positioning and/or navigation-related function for a mobile apparatus may be controlled at least in part by the instance of positioning index information.