Timed grammaticality judgment tests (TGJT) and oral elicited imitation tests (OEIT) are considered reliable and valid measures of implicit linguistic knowledge, but studies consistently observe better performances on the TGJT than the OEIT due to the different types of processing they require: comprehension for the TGJT and production for the OEIT. This study examines whether degree of access to implicit knowledge is a function of processing type. Results from a series of factor analyses suggest that the OEIT requires greater access to implicit knowledge—implying that it measures stronger implicit knowledge—than the TGJT. Furthermore, the study examines effects on construct validity of time pressure in the OEIT (uncontrolled vs. controlled) and modality in the TGJT (written vs. aural). The results indicate that the tests reached higher construct validity, or measured stronger implicit knowledge, when the OEIT employed controlled time pressure and the TGJT used aural stimuli.