This paper examines voice alternation, that is, variation between the active and passive voice in academic Englishes. The focus is on differences regarding degrees of author involvement. A previous study on the use of be-passives in fifteen varieties of academic English (Hundt, Schneider & Seoane 2016) found voice alternation to be very similar in both contact and native (ENL) varieties of English, with only American English showing a pronounced tendency towards a more frequent use of actives. A more fine-grained analysis, however, revealed highly significant interdisciplinary variation: whereas in the hard sciences the default option to express a transitive event is the passive voice, in the soft sciences, preference is often given to the active. In this paper we do not compare varieties of English but concentrate on ENL data from the entire academic sections of ICE corpora (International Corpus of English) as a whole in order to uncover the functional role of actives and passives across disciplinary areas with regard to authorial presence. The results indicate that the differences attested do not correlate with differences in authorial involvement (We discovered this versus This was discovered) since texts remain equally impersonal. Other factors, such as the increasing informalization observed in various genres, will have to be contemplated in any comprehensive study of the rhetoric of science.