The passive voice is used extensively in professional writing, making up 25% of all verb uses in published text (approximately 18,500 occurrences per million words). In spoken English, by way of contrast, its use is limited to 2% of all verbs.
The results of the survey were based on qualitative interviews conducted extensively over a six-month period.
The primary use of the passive voice in professional writing can be linked to the removal of the author (“a variation of 0.02% was measured” versus “we measured 0.02 %”) which underlines the scientific objectivity of such statements. This is in keeping with recent Western scientific tradition, though colloquial style (“With this example, we can see that….”) may be used as suits the style of the author.
Frequency of verbs
Most common (more than 100 occurrences per million words)
BE + achieved, associated, defined, expressed, measured, obtained, performed, related
Frequent (more than 40 occurrences per million words)
BE + applied, calculated, chosen, compared, derived, designed, developed, discussed, examined, explained, formed, identified, illustrated, introduced, limited, noted, observed, presented, recognized, regarded, replaced, represented, studied, suggested.
Use of Modals
Please note that the passive voice combined with modal verbs (may, can, must, should, etc) is often used to qualify statements, usually to show that a result is highly applicable, though not always true.
These effects are believed to be associated with the declining demographics seen in many European countries.
The defect rate can be interpreted in terms of batch faults per hundred samples.
Their presences must be regarded as especially undesirable.
NB: the passive “get” form is non-existent in professional writing, and even exceedingly rare in conversation.
We got informed of the dismissals via e-mail. (were?)
*Our findings got confirmed by an independent research team*. (=were).
For more information, including exercises with key, please see Passive Verbs in the Grammar Resource.