In the passive voice the subject is acted upon. The passive voice is useful when the writer needs to be sensitive (say something delicately) or needs to focus on the subject being acted upon. However, the passive voice should be used sparingly, especially in academic writing. This voice can be long-winded and slow. The use of any form of "to be" can be considered passive.
Two examples of passive voice are:
"Steps to ensure reliability and validity of research, analysis, and results were taken in the study."
"This research problem and its basis were described clearly and completely by the authors." (Calvano, 2012).
Examples of acceptable use of the passive voice are:
The tickets were sold yesterday. (The actor is not known)
The flag pole has been broken in half. (The writer is focused on the action.)
In active voice, the subject is performing the action. The active voice is widely used in the English language. The sentences above can be altered to reflect the active voice:
The researcher took steps to ensure the reliability and validity of research, analysis, and results of the study.
The authors clearly and completely described the research problem and its basis.