Scientific writing 3.0: A reader and writer's guide - Jean-Luc Lebrun, Justin Lebrun 2021

Understanding sentence length
The scientific writing style
The reading toolkit

Long sentences may cause readers difficulties. But it doesn’t quite feel fair to lump all long sentences together. Some very long sentences remain easy to read while other slightly shorter sentences are impossible to get through.

Clauses

Let’s take the next two sentences as an example:

General Sanders had never met a soldier like the new recruit from Delaware, Private Jonas Jameson, whose belligerent attitude was evident in every little undertaken action, from guard duty, to report writing, to any and all other administrative tasks. (Long but clear)

Although he knew how to cook well, due to his being stuck in a kitchen whose windows were jammed shut and whose airflow suffered due to a broken ventilator, he found himself distracted and unable to concentrate on the dish. (Long but difficult to read)

What distinguishes one sentence from the next? To understand the answer, we can’t just look at sentence length from the perspective of word count or even word length. Both of the sentences above are roughly the same length (39 vs 36 words), and neither one contains many long multisyllabic words. We need another metric by which to evaluate these two sentences: the clause.

According to the Oxford dictionary, a clause is “a unit of grammatical organization next below the sentence in rank and in traditional grammar said to consist of a subject and predicate”. Unless you’re a big fan of reading books about grammar, that explanation is likely clear as mud. To simplify, a clause is a part of a sentence that contains a subject and a verb.

For example, “He met his wife” is a sentence made up of a single clause — only one subject, he, and one verb, met. We can extend that sentence by turning it into a two-clause sentence: He met his wife while she went shopping”. We now have two pairs of subjects and verbs — he met and she went.

Notice that although the first clause could stand on its own (He met his wife is a grammatically correct sentence), the second clause cannot stand alone (when she went shopping cannot be a full sentence). We call the first type of clause that stands alone a main clause and the second type a subordinate clause (or subclause).

You could further elongate the sentence by adding a third subclause: He met his wife while she went shopping because she walked into his workplace. Or even a fourth: He met his wife while she went shopping because she walked into his workplace which was located next to the town’s public library. We’ve come this far, why not add a fifth? He met his wife while she went shopping because she walked into his workplace which was located next to the town’s public library that was under renovation. Notice how even though the content of the sentence is simple, it is beginning to become more and more difficult to read. Why? Because it contains many different subjects and many different actions, each one of which gives the reader some information:

1)He met his wife

2)This meeting happened while she was shopping

3)You can shop at his workplace

4)His workplace is located next to the town’s public library

5)The library was under renovation

Trying to piece together these disparate pieces of information within a single sentence is tiring for the reader, and may require a second read. Even though the sentence isn’t particularly long (27 words), it already feels long because of information density.

Do a little exercise and try to identify the number of clauses present in the two long sentences proposed right under the earlier heading “clauses”. Look for subjects and verb pairs. When you’re done, continue on below for the solution:

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General Sanders had never met a soldier like the new recruit from Delaware, Private Jonas Jameson, whose belligerent attitude was evident in every little undertaken action, from guard duty, to report writing, to any and all other administrative tasks.

Despite its length, the sentence only contains two clauses. Now let’s look at the second example:

Although he knew how to cook well, because he was stuck in a kitchen whose windows were jammed shut and whose airflow suffered due to a broken ventilator, he found himself distracted and unable to concentrate.

Here, we can see that the sentence’s length comes from no less than five clauses!

One clause is easy. Two are fine. Three may require some effort. Four is taxing. Five and above? You’re exhausting the reader. If you want to avoid burdening the memory of your reader, keep to an average of two clauses per sentence.

Prepositions

Prepositions are amongst the most common words in the English language, appearing in nearly every sentence, often multiple times. You’ll recognize them instantly: for, to, with, about, at, under, through, etc. How are they used? Their purpose is to add detail to whatever they follow in a sentence. For example, “the man smiled” is less precise than “the man with the balloon smiled”, which is itself less precise than “the man with the balloon smiled at the mirror. But adding too many prepositions in a single sentence is like adding detail to detail to detail until the reader is lost. Let’s look at a poorly written sentence with too many prepositions:

Researchers have observed an increase in the amount of energy generated by the splitting of uranium atoms in simulations with constraints removed.

Notice how you could place a period before every preposition and the sentence would still make sense. Each preposition simply elongates the sentence with additional detail. If you remove all meaningful information, you can see the bare sentence structure:

“A have observed differences in B of C of D in E with F”. Without even reading the sentence, you can already tell it is overly complex. Let’s take another look at the sentence, but rewritten to remove excessive prepositions:

Researchers have observed increased energy generation when splitting uranium atoms in unconstrained simulations.

With only two prepositions left, the text is easier to read. Let’s take a look at the different ways you can remove excessive prepositions from your text:

Compound nouns: The collector of books → The book collector

Possessive case: The owner of the jeep → The jeep’s owner

Passive to active: He was booed offstage by the crowd → The crowd booed him offstage

Use adverbs: He cleaned the floor with great vigor → He cleaned the floor vigorously

Use precise verbs: He looked at the wall carefully → He inspected the wall