People require 25% more time to understand simple passive than simple active sentences.—Miller (1962)

Readers are likely to feel that they are reading prose that is clear and direct when

(1) the subjects of the sentences name the cast of characters, and

(2) the verbs that go with those subjects name the crucial actions those characters are part of.

—Williams (1990)

Activate the passive. The passive voice is an occupational hazard in many fields: Science, technical specialties, academic writing, and bureaucracy are all rich sources of the passive voice. It’s so common that most writers in such fields don’t even know when they’re using it—and if they do know, they’re proud of themselves for doing so. They think they sound professional. … Passive voice raises another problem for web writers: It means more words. —Kilian (1999)

Governments, politicians, and officials of all kinds love the passive because individual actions are buried beneath a cloak of collective responsibility.  --BBC

While the literature on the effect of active versus passive voice is mixed, active voice can be effectively used in Web writing. Not only do readers move more quickly through active voice text, but they prefer it and feel more familiar with it. Readers may even encode passive voice text in active voice. Writers can save space on the page and mental effort for the reader by using active voice when it suits the content’s purpose. —Spyridakis (2000)