Impersonal passive constructions allow you to report information without identifying the source, creating a formal and objective tone commonly used in academic writing and news reports.
Quick tip: Two forms: 'It is said that he left' OR 'He is said to have left' - same meaning, different focus.
It + passive reporting verb + that
Use It is said/believed/thought + that for formal reports without naming a source.
It is said that the company will expand next year.
It is believed that the artifact dates back centuries.
It is thought that stress affects health significantly.
Subject + passive + to-infinitive
Use subject + is said/believed + to + verb as an alternative form.
The company is said to be expanding next year.
She is believed to have discovered the solution.
They are thought to be working on a new project.
Perfect infinitive for past
Use to have + past participle when the reported action happened before the reporting.
He is said to have left the country.
The painting is believed to have been stolen in 1990.
They are reported to have reached an agreement.
Common mistakes
Not "It is believed he left." — say "It is believed that he left.". Include 'that' in formal style.
Not "He is believed left." — say "He is believed to have left.". Need 'to have + past participle' for past.
Not "It is said she is rich." — say "It is said that she is rich.". Use 'that' after 'It is said'.
Practise it
Try converting between the two forms: 'It is believed that she discovered...' becomes 'She is believed to have discovered...'.