1. A non-transitory computer-readable medium storing computer-executable instructions that when executed by a computer cause the computer to perform a method, the method comprising: receiving a search string being input to a search system to retrieve stored artifacts relevant to the search string; determining a first certainty level associated with a first portion of the search string and a second certainty level associated with a second portion of the search string, where the certainty level associated with a given portion of a search string estimates a level of certainty that a user that entered the search string has in the accuracy of the portion of the given search string; executing the search string to retrieve artifacts relevant to the search string; and ranking the retrieved artifacts to produce a search result, where the ranking is based, at least in part, on whether a retrieved artifact is relevant to the first portion or the second portion of the search string.