Parallel construction in academic text

Parallel construction is one of those mechanisms that you notice only when it is violated, making you stumble as you read. Try this: “The monthly mean maximum temperatures were 20 °C, 23 °C, 27 °C, and 30 °C in December, January, and February, respectively.” Eh? What was that? Is a month missing or is one value surplus to requirements? Here, we have two series and they are not ‘parallel’: one contains four items whereas the other contains three, leading to a mismatch. Here is another but a bit more subtle example: “The objectives of the study were to identify trends, to assess their impact on population, and finding ways to predict their effects a decade ahead.” Using ‘to find’ instead of ‘finding’ makes the series ‘parallel’. 

These examples show that a piece of text that is not parallel belies expectations1 and thus distracts readers whereas parallel text makes for a smoother reading experience. Let us examine the concept in a bit more detail. 

What is parallel structure 

A series of items, or a list, is considered parallel when each item in the series conforms to the same grammatical or syntactical structure:  each item can be a single word, a phrase, a clause, or a complete sentence—and whatever it may be, all items in that list must then be the same (words, phrases, clauses, etc.) and presented in the same sequence with identical punctuation (when required). Each such item can even be a question, the list serving as a series of questions. Here are some well-known examples. 

• Single words: “I have nothing to offer but blood, toil, tears and sweat.” Winston Churchill 

• Phrases: “Government of the people by the people, for the people.” Abraham Lincoln 

• Clauses: “Happiness is when what you think, what you say, and what you do are in harmony.” Mahatma Gandhi 

• Sentences: “The time for the healing of the wounds has come. The moment to bridge the chasms that divide us has come. The time to build is upon us.” Nelson Mandela 

It is no accident that all the above examples are from politicians who were also powerful speakers, speakers who were masters of the rhetoric.2 

Parallel structure in academic writing 

Whereas politicians aim to influence their audience, academic writers aim to inform and to explain; yet, parallel structure has its place in academic writing too because information presented using a parallel structure is easier to assimilate and even to recollect. In fact, the concept has been researched upon, and the finding was clear: “Reading time for the second clause of a conjoined sentence was found to be faster when the clause was structurally similar to the first clause than when the clausal structures differed.”3 

Parallel structure also makes writing more concise because the authors use the structure itself to avoid repetition, as in “Sodium chloride was dissolved in water; copper sulfate, in xylene; and potassium nitrate, in benzene” or “bacteria were collected from soil; fungi, from infected leaves; and spores, from air just above the crop canopy”. Incidentally, note the use of commas and semicolons in these examples. 

Although the two examples given above are of a single sentence, parallel structure operates across multiple sentences, typically in lists of bullet points, and violations of parallel structure are often seen with such lists. In reports, conclusions and recommendations are often presented as lists and it is particularly important to ensure that items in such lists are parallel. In the following table, the right-hand column presents the conclusions of a study whereas the left-hand column presents the recommendations based on those conclusions. Note the parallel structure in both the columns: one uses declarative sentences whereas the other uses direct commands. 

Ensuring parallel structure 

However, to ensure parallel structure requires some knowledge of grammar: a recent study4 traced the difficulty in achieving parallel structure to the inability to identify the appropriate part of speech – verb, noun, adjective – that needed to be parallel. 

Final tips 

• Read aloud any text that requires parallel structure: disturbed rhythm while reading aloud is a reliable indicator of unparallel structure. 

• Brush up your grammar so that you can pinpoint the part of speech that needs to be the same in each item in the series to ensure that it is parallel.  

References 

1 Krohn T. n.d. Reader Expectations: To write clearly, we must first understand what readers expect 
https://www.reallywrite.com/learn/reader-expectations-clear-writing 

2 Atkinson M. 2004. Lend Me Your Ears: all you need to know about making speeches and presentations, p. 195. London: Vermillion (Ebury Press, Random House). 376 pp. 

3 Frazier L, Taft L, Roeper T, Clifton C, and Ehrlich K. 1984. Parallel structure: a source of facilitation in sentence comprehension. Memory & Cognition 12: 421–430 

4 Sari A P and Oktavia W. 2023. English students’ difficulties with parallel structure in the structure and written expression section in TOEFL test. Journal of English Language and Teaching 12: 106–121