The present study aims at measuring the level of correspondence between the problems related to increased cognitive effort reported by simultaneous interpreting trainees in their retrospective verbal protocols and problems indicators identified in the target texts. The study triangulates process analysis (retrospective protocols) with product analysis (manual comparison of source and target texts). The corpus of the study consists of about 75 hours of recordings of 240 interpreting outputs and the recordings of 5,005 retrospective comments. The results imply that that increased cognitive load involved in simultaneous interpreting and the resulting cognitive effort experienced by trainee interpreters is not always manifested in the product.