It is not wrong to write in the passive voice when appropriate. There are 5 specific cases in which passive voice is perfectly acceptable. However, let's first clarify the difference between active voice and passive voice.
For active voice, the subject goes first, followed by the verb, then the object: S-V-O.
For passive voice, the object is first, followed by the verb, then the subject: O-V-S
Active: Bryan threw the football.
Passive: The football was thrown by Bryan.
These sentences are saying the same thing, but in the active voice, the focus is more on Bryan and in the passive voice, the focus is on the football. Additionally, when we use the passive voice, the sentence is typically formed of the verb be--is, was, or has been--and the past participle form of the verb (i.e., threw versus thrown).
In some instances, the subject can even be dropped in the passive voice.
Passive: The football was thrown. O-V
We do tend to avoid the passive voice for different reasons. It is criticized as tending to be more evasive, vague, indirect, and it can make the sentence "wordy." Remember, the goal is to be as concise and clear as possible when writing academic papers for humanities and social sciences. This is when active voice is highly encouraged in order to focus on the different ideas of the researchers or the relationships between concepts and ideas of the writer and those of the ideas of the researchers being discussed. When too many passive sentences are present, there can be confusion as to who did, said, or thought what.
The 5 cases when passive voice is appropriate and even sometimes ideal:
- The actor is unknown:
- "A 120-foot feline figure dating back to 200 B.C. was carved into a hill in Peru."
- Here, we do not know who carved it.
- The actor is irrelevant:
- "The World War II Museum was built in New Orleans."
- Here, we are not interested in who built it.
- It is a general truth:
- "Rules are made to be broken."
- Here, the action can be performed by whomever, wherever.
- To emphasize the person or thing being acted on:
- "Polio has been eradicated in the United States due to the groundbreaking development of the polio vaccine. There has not been a single case recorded by the CDC since 1979."
- These are often great topic sentences.
- You are writing in a scientific genre that relies on the passive voice, most notably in the Materials and Methods of lab reports:
- "A solution of sodium hydroxide was tittered until neutralized into a sample of hydrogen chloride."
- This emphasizes the experimental process.
- We assume our audience knows it is you performing the action.
Note: Scientific disciplines have started to move towards the active voice but in academic writing, you will find that the passive voice is most often found in published reports such as these.
SAT Tip: Strong active voice sentences are more often the correct response. I have recently seen the passive voice pop up more, and in complex ways, on the exam but when in doubt, chose the active voice:
Passive choice: Eye contact with the raging bull was
avoided by me.
Active choice: I avoided eye contact with the raging bull.
I hope that helps!