1. A computer-implemented method comprising: receiving a first series of keystrokes that correspond to an initial portion of a partial search query input by a user, and a second series of keystrokes that correspond to a subsequent portion of the partial search query input by the user; determining a first time delay that is associated with a rate of input of the keystrokes that correspond to the initial portion of the partial search query, based on one or more time intervals between keystrokes of the first series of keystrokes that correspond to the initial portion of the partial search query input by the user; determining a second time delay that is associated with a rate of input of the keystrokes that correspond to the subsequent portion of the partial search query input by the user, based on one or more time intervals between keystrokes of the second series of keystrokes that correspond to the subsequent portion of the partial search query input by the user; determining a threshold amount based on a statistical measure associated with two or more time intervals between successive keystrokes of the first series of keystrokes that correspond to the initial portion of the partial search query input by the user; determining that the second time delay exceeds the first time delay by the threshold amount that is determined based on the statistical measure, based on a comparison of the first time delay and the second time delay; and in response to determining that the second time delay exceeds the first time delay by the threshold amount that is determined based on the statistical measure, transmitting, to a search engine, a search request for the partial search query.