An example method includes obtaining a plurality of data items. Each data item includes an indication of a particular location, an indication that a wireless signal from a first access point was observed at that location, and an indication of a time at which the wireless signal from the first access point was observed at that location. The method also includes determining a locational stability of the first access point based on the data items. Determining the locational stability of the first access point includes clustering the plurality of data items into one or more clusters based on the locations indicated in the plurality of data items, determining whether the N most recent data items are associated with a common cluster, and determining whether a time span between the N most recent data items exceeds a threshold period of time.