Style guides for scientific English frequently suggest avoiding the passive voice (Day & Sakaduski, 2011), as it is considered to weaken writing clarity. Yet research has shown that the passive is highly common in academic prose (Biber et al., 1999), particularly in scientific writing (Swales, 2004). While a few studies have investigated the passive in published scientific writing, such as medicine and physics (e.g., Hiltunen, 2016), engineering is poorly represented and understood in research on disciplinary discourse but especially on student writing. Despite increasing awareness of the challenges engineering graduate students have in writing high-stakes research genres such as the master’s thesis, little attention has been given to engineering student writing. Furthermore, specificity is a key principle in English for specific purposes (ESP) research (Hyland, 2002), yet how far we should go with this concept is still an open question. Using corpus-based methods, we present findings of a comparative analysis of the use of the passive voice in engineering master’s theses. Specifically, we systematically compare the frequencies, forms (including tenses and clause types), and functions of the passive voice across five sub-disciplines. Data consist of specialized corpora of 150 methods chapters of master’s theses in chemical, civil, electrical, industrial, and mechanical engineering. Our data show that 52% of the verbs were in the passive, and no variation was found in terms of overall frequency. Findings, however, indicate variation in the passive forms and functions across sub-disciplines. While variation also exists in verb activity types, research-oriented verbs were most frequently used by all sub-disciplines, most likely due to the part-genre of the corpora. Supporting previous research (Huddleston, 1971; Swales, 2004), certain verbs are nearly always in the passive while others rarely are. The presentation begins by reporting and discussing the results, followed by implications for research in ESP research and teaching.
2021.