Correct Parallel Structure — Recognize and correct errors in parallel structure.

Historical Context & Motivation

The principle of parallel structure—also called parallelism—has roots stretching back to the earliest Western rhetorical traditions, where balanced and symmetrical phrasing served as the hallmark of persuasive speech and elegant prose. Greek and Roman rhetoricians recognized that when coordinated elements share the same grammatical form, the resulting sentence achieves a rhythmic balance that enhances both clarity and memorability. This concern with structural balance has persisted through centuries of prescriptive grammar, becoming codified in modern style guides and standardized assessments such as the PRAXIS Core Writing exam. For aspiring educators, understanding parallel structure is doubly important: you must demonstrate mastery of it on your certification test and, subsequently, model it for your own students.

The persistent emphasis on parallelism across these milestones reflects a simple but profound insight: when writers coordinate two or more elements—whether words, phrases, or clauses—the reader's cognitive burden is reduced if those elements share the same grammatical pattern. Faulty parallelism, by contrast, forces readers to re-parse a sentence, disrupting comprehension and undermining the writer's credibility. On the PRAXIS Core Writing exam, test items targeting this skill typically present a sentence with an underlined portion containing a coordination error; your task is to identify the version that aligns every coordinated element in the same grammatical form.

Core Principles & Definitions

At its core, parallel structure requires that items joined by coordinating conjunctions (and, but, or, nor, yet, so), correlative conjunctions (both…and, either…or, neither…nor, not only…but also), or listed in a series share the same grammatical form. Whether those items are single words, phrases, or subordinate clauses, they must match in part of speech and syntactic function. Mastery of this principle depends on understanding five foundational ideas that govern how parallelism operates at different levels of sentence architecture.

Visual Explanation — Mapping Parallel Structure

The following diagram illustrates how a sentence with a coordinated series should align its elements grammatically. On the left, a faulty sentence mixes grammatical forms; on the right, the corrected version ensures every element shares the same structure. The connecting lines highlight where each coordinated element branches from the conjunction, making the required symmetry visually explicit.

Notice how the diagram makes the structural mismatch visible: the infinitive 'to write' is highlighted in red because it does not match the gerund pattern established by 'reading' and 'hiking.' On the PRAXIS exam, you should mentally construct this kind of branching diagram whenever you encounter a sentence with coordinated elements. Ask yourself: does each branch carry the same grammatical form? If not, the sentence contains a parallelism error.

How Parallel Structure Works — Types and Triggers

Parallel structure errors arise in predictable contexts, and recognizing these trigger patterns is the key to both identifying and correcting them efficiently. The PRAXIS Core Writing exam tests parallelism across four primary construction types, each governed by a specific grammatical trigger. Understanding these types allows you to approach test items systematically rather than relying on ear alone.

Type 1 — Coordinating Conjunctions (FANBOYS)

When for, and, nor, but, or, yet, so join two or more elements, those elements must match in grammatical form. This is the most frequently tested type. Consider: 'The principal values punctuality, creativity, and being dedicated.' The first two items are abstract nouns, but the third shifts to a gerund phrase. The correction: 'The principal values punctuality, creativity, and dedication.'

Type 2 — Correlative Conjunctions

Correlative conjunctions work in pairs—both…and, either…or, neither…nor, not only…but also—and the grammatical structure that follows the first half must be mirrored after the second half. A common PRAXIS-style error: 'The new policy not only affects class schedules but also the budget for extracurriculars.' After 'not only' we have a verb phrase ('affects class schedules'), so after 'but also' we need a verb phrase too: 'but also reduces the budget for extracurriculars.'

Type 3 — Comparisons (than / as)

Comparisons using 'than' or 'as…as' require structural symmetry on both sides of the comparison word. Faulty: 'Writing lesson plans is more time-consuming than to grade papers.' The subject is a gerund phrase, so the comparison element must also be a gerund phrase: 'Writing lesson plans is more time-consuming than grading papers.'

Type 4 — Lists and Series

When a sentence presents a list—often introduced by a colon or embedded in a series—every item must share the same form. This type appears frequently on the PRAXIS because longer lists increase the likelihood of a form mismatch in the final item. Consider: 'The workshop covered how to differentiate instruction, creating formative assessments, and classroom management strategies.' This list mixes an infinitive clause, a gerund phrase, and a noun phrase. A parallel revision: 'The workshop covered differentiating instruction, creating formative assessments, and developing classroom management strategies.'

Common Error Patterns & Classification

Research on standardized writing assessments reveals that certain parallelism errors recur with high frequency. Recognizing these error patterns accelerates your ability to spot faulty parallelism under timed conditions. The following classification table organizes the most common patterns, illustrating each with a faulty example and its corrected counterpart. After the table, a detailed flowchart will guide you through the diagnostic reasoning process.

Worked Example — PRAXIS-Style Question

The following worked example replicates the format of a PRAXIS Core Writing selected-response item, walking you through every reasoning step from identification to correction. As you study this example, pay attention to the systematic approach: locate the trigger, isolate the coordinated elements, label their forms, and select the answer that aligns all elements in the same structure.

Strategies & Common Pitfalls

While the rule for parallel structure is straightforward in principle—coordinate elements must share the same grammatical form—certain sentence constructions make errors more difficult to detect. The table below contrasts effective test-taking strategies with common pitfalls that lead to incorrect answers on the PRAXIS Core Writing exam.

Connection to Advanced Writing Concepts

Parallel structure does not exist in isolation; it intersects with several other PRAXIS Core Writing competencies and broader principles of effective composition. As a future educator, understanding these connections will help you not only answer exam questions but also teach writing with greater depth and coherence. The table below maps parallel structure to related concepts you will encounter both on the PRAXIS and in your professional practice.

Looking beyond the PRAXIS exam, the concept of parallelism connects to the broader field of rhetorical grammar—a pedagogical approach that positions grammar instruction within the context of effective communication rather than mere rule-following. When you eventually teach writing, framing parallel structure as a tool for clarity and persuasion—rather than simply a rule to avoid errors—will help your students internalize the concept at a deeper level. Rhetorical theorists from Aristotle to contemporary composition scholars such as Martha Kolln have argued that structural balance is not an arbitrary convention but an intrinsic feature of how humans process language: symmetrical patterns reduce cognitive load and signal logical relationships between ideas.

Practice Problems

The following five problems progress from conceptual understanding to critical analysis. Each problem mirrors the format and difficulty level you will encounter on the PRAXIS Core Writing (5723) exam. Attempt each one before reading the answer.

Summary — Parallel Structure at a Glance