Writing Tips >> Parallelism
Parallelism refers to the use of expressions that have the same grammatical structure in one sentence. Parallel construction usually applies to similar ideas. These ideas may be expressed in noun phrases, verb phrases, or clauses. A sentence can be understood more easily when each idea is expressed in a similar form. The following table shows some examples of parallel expressions in sentences.
| Types of Parallel Expressions | Examples (parallel expressions highlighted in green) |
| noun phrases | The study evaluated Method A, Method B, and Method C. |
| verb phrases | The study evaluated four models and proposed a mixed model. |
|
clauses (subject-verb-adjective) |
Method A is faster while Method B is more accurate. |
The following table shows how to improve the clarity of a sentence by writing parallel expressions.
|
Incorrect (noun, noun phrase, clause) |
The experiment measured the conductivity, melting point, and how dense the hardened mixture was. |
|
Correct (noun, noun phrase, noun) |
The experiment measured the conductivity, melting point, and density of the hardened mixture. |
When an article precedes a series of nouns, the article should be used before either the first noun or each noun. The following table demonstrates how to achieve parallel construction with articles.
| Incorrect | The conductivity, melting point, and the density of the hardened mixture were measured. |
|
Correct “the” before the first noun |
The conductivity, melting point, and density of the hardened mixture were measured. |
|
Correct “the” before each noun |
The conductivity, the melting point, and the density of the hardened mixture were measured. |
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