Use active verbs and not passive verbs. Active verbs are when the sentence’s subject does something. Passive verbs are when the sentence’s subject has something done to it. In the examples below, the subjects are the policy and the study.

The policy encourages firms to…

Not

Firms are encouraged by the policy to…

The study shows a trend

Not

A trend is shown by the study

However, write “It is expected”, rather than “One expects”. Using “one” is considered old-fashioned and we refer to ourselves at ONS as “we”.