In one embodiment, a technique is provided for estimating and using an expected error of a position estimate of a wireless local area network (WLAN)-enabled mobile device. The WLAN-enabled mobile device received signals transmitted by a plurality of WLAN access points that are in range. A position of the WLAN-enabled mobile device is estimated based on the signals from one or more of the plurality of WLAN access points. An expected error of the position estimate is estimated based on a combination of correlated parameters, such as a spatial spread of geographic positions of the one or more WLAN access points, the signal coverage areas of the one or more WLAN access points, and a number of the one or more WLAN access points. Based on the expected error, the position estimate may be weighted or excluded from use in deriving a position, speed, or direction of travel.