Good writers employ strategies that make it easy for their readers to understand what they want to communicate.

Consistency in Number

Inconsistent: He has won awards and is at the top of their game.
Consistent: They have won awards and are at the top of their game OR He has won awards and is at the top of his game.

For example: I invited Sam to the party. I don’t know if they are coming or not.

Consistency in Person

Inconsistent: Before you apply for a work permit, one must show proof of Canadian citizenship or landed immigrant status.

Consistent and appropriate for business writing: Before you apply for a work permit, you must show proof of Canadian citizenship or landed immigrant status.

Consistent and appropriate for academic writing: Before students apply for a work permit, they must show proof of Canadian citizenship or landed immigrant status.

Consistency in Tense

Inconsistent: When the teacher entered the classroom, the students sit up straight.
Consistent:  When the teacher enters the classroom, the students sit up straight OR When the teacher entered the classroom, the students sat up straight.

Consistency in Voice (active/passive)

Avoid using both active and passive voice within a single sentence. Use active voice whenever appropriate.

Inconsistent (active + passive): Weather forecasters expect continued cold weather throughout January but warmer weather in March is anticipated.
Consistent (active + active): Weather forecasters expect continued cold weather throughout January but anticipate warmer weather in March.

Consistency in Comparatives and Listed Elements: Parallelism

Sentences that contain lists or comparison need parallel structure.  Parallelism creates a good rhythm in a sentence and also ensures that each item in the list or comparison is given equal weight. When items are in parallel, each item is expressed in the same grammatical term. In other words, you can have a list of nouns, or a list of verbs, or a list of adjectives, but you cannot have a list that mixes nouns, verbs, and adjectives.

Inconsistent: To live more sustainably, people must recycle, be buying from local stores, and to stop driving unnecessarily.

Parallel verbs: To live more sustainably, people must recycle, buy from local stores, and stop driving unnecessarily.

Inconsistent: Physicians treating anorexics must treat the physical trauma associated with the disease as well as the underlying psychological disorders of low self-esteem, being anxious, and having depression.

Parallel nouns: Physicians treating anorexics must treat the physical trauma associated with the disease as well as the underlying psychological disorders of low self-esteem, anxiety, and depression.

Inconsistent: The communication styles in high-context and low-context cultures differ in terms of how they confront people and responding to criticism.

Parallel phrases: The communication styles in high-context and low-context cultures differ in terms of how they confront others and how they respond to criticism.

Inconsistent: Kayaking on a calm lake is much easier than rough waters.

Parallel comparison: Kayaking on a calm lake is much easier than kayaking on rough waters.