3.8 Parallel Structure and Logical Comparisons

3.8 Parallel Structure and Logical Comparisons

Parallel constructions make coordinated ideas easier to follow. Check lists, paired conjunctions, and comparisons for matching grammatical roles and logical categories.

Parallel Structure in Lists and Series

Parallelism requires that coordinate ideas—elements connected by coordinating conjunctions (and, but, or)—be expressed in identical grammatical forms. If the first item in a series is a gerund (-ing noun), all subsequent items must be gerunds; if the first is an infinitive (to + verb), all subsequent items must be infinitives.

Coordinate Series Patterns

Note on Infinitives in Series: In an infinitive series, you may repeat the particle to with every item ("to read, to write, and to speak") or include to only before the first item ("to read, write, and speak"). Keep the series easy to follow; do not treat an otherwise grammatical mixed repetition as an automatic error.

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Correlative Conjunctions and Syntactic Balance

Correlative conjunctions are paired conjunctions that link equivalent syntactic units:

• not only... but also
• either... or
• neither... nor
• both... and
• whether... or

The Symmetry Rule

Whatever grammatical structure follows the first half of a correlative pair must be mirrored precisely by the structure following the second half.

• If not only is followed by a verb, but also must be followed by a verb.
• If not only is followed by a prepositional phrase, but also must be followed by a prepositional phrase.

Common Correlative Errors

• Faulty: "The newly appointed superintendent not only promised to increase faculty compensation but also student counseling services."
  • Analysis: Not only is followed by an infinitive verb phrase (promised to increase...), while but also is followed by a simple noun phrase (student counseling services). The structures are unbalanced.
• Corrected: "The newly appointed superintendent promised not only to increase faculty compensation but also to expand student counseling services." (Infinitive phrase matches infinitive phrase).
• Alternative: "The newly appointed superintendent promised to improve not only faculty compensation but also student counseling services." (Noun phrase matches noun phrase).

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Illogical and Incomplete Comparisons

Comparisons must be grammatically parallel and logically sound. On the Praxis Core Writing test, comparison errors take three distinct forms:

1. Comparing Apples to Oranges (Faulty Comparisons)

A comparison is illogical when it compares two fundamentally different classes of entities, such as comparing a characteristic of an institution directly to the institution itself:

• Illogical: "The curriculum of this private academy is far more demanding than the public school district."
  • Problem: This compares a curriculum (an academic program) to a district (a geographic and administrative organization).
• Corrected (Singular): "The curriculum of this private academy is far more demanding than that of the public school district." (that of = the curriculum of).
• Corrected (Plural): "The standardized test scores of suburban students remain higher than those of rural students." (those of = the scores of).

2. Omission of "Other" or "Else" in Comparisons within a Group

When comparing an individual entity to all other members of the same category, you must use the word other or else to exclude the entity from the group with which it is being compared:

• Illogical: "Maya is faster than any student in her physical education class."
  • Problem: Maya is a student in her physical education class. The sentence asserts that she is faster than any student, which implies she is faster than herself!
• Corrected: "Maya is faster than any other student in her physical education class."

3. Incomplete Comparisons

An incomplete comparison fails to provide the second term of the comparison, leaving the reader with an ambiguous or dangling relationship:

• Incomplete: "Students who participate in extracurricular speech and debate perform significantly better."
  • Question: Better than what? Better than they did before? Better than students who do not participate?
• Completed: "Students who participate in extracurricular speech and debate perform significantly better than their peers who do not participate."

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Strategic Praxis Core Checklist for Modifiers and Parallelism

1. Check the introductory phrase: If a sentence begins with an -ing participle, -ed participle, or to + verb, verify that the noun immediately following the comma is the entity actually performing that action.
2. Verify adverbs of limitation: Ensure that words like only, nearly, and almost are positioned directly in front of the specific word or number they modify.
3. Inspect series and lists: Scan series joined by and or or. Ensure all items share matching grammatical forms (all gerunds, all nouns, all full clauses).
4. Check correlative pairs: When you encounter not only... but also or either... or, ensure that the grammatical units following both conjunctions are identical.
5. Look for comparison markers: When sentences use more than, less than, or as... as, check that the two entities being compared are logically equivalent and utilize that of or those of when comparing attributes.