1. A method comprising: identifying, by a computing device, a size of a geo-fence, the size of the geo-fence comprising an area encompassed by the geo-fence; selecting, based on the size of the geo-fence, a location determination module from multiple location determination modules; identifying, by the computing device, a size of a position uncertainty area for the location determination module, the position uncertainty area being based on an estimated accuracy error of a location for the computing device provided by the location determination module and being specific to the location determination module; and determining, by the computing device, occurrence of one or more geo-fence events for the geo-fence based on a confidence value for a geo-fence breach condition satisfying a threshold confidence value, the threshold confidence value varying based at least in part on a ratio of the size of the geo-fence and the size of the position uncertainty area.