Using the Passive Voice in Scientific Writing

When to use passive voice?

• Science fields: chemistry, biology, physics, math, computer science.
• Medical fields: patient records, medical journals.
• Legal fields: client records, proceedings, notes.

Why use passive voice?

• Let the facts stand on their own!
• Removes some accusations of bias (who did it, how many did it.)
• Presents an “air” or feeling of logic.

Examples

Unscientific

I did this experiment several times. Each time I got the same results. After the last time, I was convinced that I was right. The new bacteria must have caused all the problems we found in our patients.

Scientific

The procedure was repeated until there was certainty regarding the results. The problems encountered by the patients were caused by the bacteria.

Rule Summary for Changing Sentences from Active to Passive

• Start with active-voice sentence: Prof. Sorensen ate the apple.
• Remove the subject from the sentence: __________ ate the apple.
• Move the object to the subject “slot”: The apple ate.
• Add “to be” before the verb in the same tense as the original verb: The apple was ate.
• Change the original verb to its past participle* form: The apple was eaten.
• (Optional) Add “by” and the original subject after the verb: The apple was eaten by Prof. Sorensen.

*-For many verbs, the past participle is the same form as for past tense, but there are many irregular verbs with special forms for past participle. Most dictionaries will identify these.

Verb Examples

• Past tense form: Ate
• Past participle form: Eaten

• Past tense form: Measured
• Past participle form: Measured

• Past tense form: Gave
• Past participle form: Given

Developed by Dr. Charlene Sorenson, Gallaudet University Department of Chemistry, and Dr. Tonya Johnson, Gallaudet University English Department.