Agency is one of the most important considerations to bear in mind when writing a report, or when reading one. It will greatly influence the tone and the interpretation of the subject matter, and a good understanding of agency will really help when writing any type of document, not just academic ones. The agent is interpreted as “the thing that is doing the action in the sentence”, but it is not necessarily the grammatical subject. For example:

I walk my dog  – the agent is myself (or I)

The dog is walked by me – the agent is still myself (or me)

In addition, you can have sentences where something happens without any agent:

The sun rises. Ice melts.

The choice of agent is important when trying to cultivate an impersonal tone. For example, instead of writing :

We found this to be true

Change the agent to :

The results indicate this to be true.

Also, subtle differences in meaning can be created by  changing the agent of a verb. Compare:

The rate increased over time / The rate was increased over time.

Agency covers a very broad area of language, and is impossible to summarise in such a short space. However, it offers an valuable  insight into the perspective of the author and how they represent a topic.