Parallel Structure — Keeping Lists and Sentences Balanced in Technical Documentation

In this tutorial, you will learn about Parallel Structure. We cover key concepts, practical examples, and best practices to help you master this topic.

Parallel structure means using the same grammatical form for items that serve the same function. Lists, bullet points, headings, and series of steps should all use consistent patterns. Without parallel structure, readers must work harder to understand the relationship between items.

In this lesson, you will learn how to identify and fix non-parallel structures in your documentation.

What You'll Learn

You will understand parallel structure principles, apply parallelism to lists and sentences, and review documentation for consistent grammatical forms.

Why It Matters

Parallel structure makes content predictable and easier to scan. When readers know what to expect, they Process information faster.

Real-World Use

DodaTech rewrote all numbered steps to start with imperative verbs. Install, configure, verify replaced Installing, configuring, verification. User testing showed 20 percent faster task completion.

flowchart LR
  A[Item 1] --> B[Verb + Object]
  A --> C[Verb + Object]
  A --> D[Verb + Object]
  D --> E[Consistent Pattern]
  E --> F[Easy to Scan]
  A:::current
  classDef current fill:#f90,color:#fff,stroke:#333,stroke-width:2px

Parallel Lists

All items in a bullet or numbered list should use the same grammatical form. If one item starts with a verb, all items should start with a verb.

If one item is a complete sentence, all items should be complete sentences. If one item is a noun phrase, all items should be noun phrases.

List introductions should complete the sentence for each item. Each item should make a complete sentence when combined with the introduction.

# Non-parallel (different forms)
DodaZIP can:
- Compress files (verb phrase)
- It also decompresses archives (full sentence)
- Support for multiple algorithms (noun phrase)

# Parallel (all verb phrases)
DodaZIP can:
- Compress files
- Decompress archives
- Support multiple algorithms

# Non-parallel steps
1. Installing the package
2. Configure the settings
3. Verification of output

# Parallel steps (all imperative)
1. Install the package
2. Configure the settings
3. Verify the output

Parallel Sentences

Items in a series within a sentence should also use parallel structure. The system compresses, decompresses, and verifies archives is parallel.

Non-parallel: The system compresses files, can decompress them, and verification. Compresses and can decompress are different forms. Verification is a noun.

Use parallel structure in headings. If one heading uses an -ing form, all headings at the same level should use -ing forms.

# Non-parallel headings
## Installing the Software
## Configuration Steps
## To Verify Installation

# Parallel headings
## Installing the Software
## Configuring the Settings
## Verifying the Installation

Common Mistakes

1. Mixed Verb Forms

Starts with an imperative verb but switches to gerund or infinitive. Install, configuring, verifying instead of Install, configure, verify.

2. Mixed Sentence Types

Some list items are complete sentences, others are fragments. Make all items the same type.

3. Inconsistent Starters

Starting list items with different parts of speech. Some start with verbs, others with nouns, others with adjectives.

4. Non-Parallel Headings

Using Installing, Configuration, To Verify at the same heading level. Use consistent form.

5. Mixed Voice

Switching between active and passive in the same list. Compress files, verify output, the archive is created.

6. Inconsistent Prepositions

Start items with different prepositions. In the terminal, on the server, from the menu. Use consistent prepositions.

7. Parallelism in Code Comments

Mixing comment styles. Uses # docstring here and // comment here in the same file.

Practice Questions

1. What is parallel structure?

Using the same grammatical form for items that serve the same function in a list, sentence, or series.

2. Why does parallel structure matter?

It makes content predictable and easier to scan. Readers process parallel structures faster.

3. How should numbered steps be formatted?

All steps should start with an imperative verb. Install, configure, verify instead of installing, configuration, verification.

4. What happens when headings are not parallel?

Readers cannot predict heading patterns. The document feels disorganized.

5. Challenge: Find 10 non-parallel structures in documentation you use. Identify the type of non-parallelism for each. Rewrite each to be parallel.

FAQ

Mini Project

Audit a documentation page for non-parallel structures. Check lists, headings, numbered steps, and sentences with series. Identify every non-parallel item and rewrite it. Verify all items at the same level use consistent grammatical forms.

What's Next

Next: Lists and Bullets