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Structuring Effective Sentences

Good technical communication consists of clear, graceful sentences that convey information economically. This section describes six principles for structuring effective sentences:

Sentences are often easier to understand and more emphatic if new information appears at the end. For instance, if your company has labor problems and you want to describe the possible results, structure the sentence like this:

Because of labor problems, we anticipate a three-week delay.

In this case, three-week delay is the new information.

If your readers already expect a three-week delay but don’t know the reason for it, reverse the structure:

We anticipate the three-week delay in production because of labor problems.

Here, the new and important information is labor problems.

Try not to end the sentence with qualifying information that blunts the impact of the new information.

Put references to time and space at the beginning of the sentence, where they can provide context for the main idea that the sentence expresses.

Since the last quarter of 2014, we have experienced an 8 percent turnover rate in personnel assigned to the project.

On the north side of the building, water from the leaking pipes has damaged the exterior siding and the sheetrock on some interior walls.

Sometimes sentence length affects the quality of the writing. In general, an average of 15 to 20 words per sentence is effective for most technical communication. A series of 10-word sentences would be choppy. A series of 35-word sentences would probably be too demanding. And a succession of sentences of approximately the same length would be monotonous.

In revising a draft, use your software to compute the average sentence length of a representative passage.

Avoid Overly Long Sentences How long is too long? There is no simple answer, because ease of reading depends on the vocabulary, sentence structure, and sentence length; the reader’s motivation and knowledge of the topic; the purpose of the communication; and the conventions of the application you are using. For instance, you use shorter sentences in tweets and text messages than in reports.

Often a draft will include sentences such as the following:

The construction of the new facility is scheduled to begin in March, but it might be delayed by one or even two months by winter weather conditions, which can make it impossible or nearly impossible to begin excavating the foundation.

To avoid creating such long sentences, say one thing clearly and simply before moving on to the next idea. For instance, to make this difficult 40-word sentence easier to read, divide it into two sentences:

The construction of the new facility is scheduled to begin in March. However, construction might be delayed until April or even May by winter weather conditions, which can make it impossible or nearly impossible to begin excavating the foundation.

Sometimes an overly long sentence can be fixed by creating a list (see the Guidelines box "Revising Headings.")

Avoid Overly Short Sentences Just as sentences can be too long, they can also be too short and choppy, as in the following example:

Customarily, environmental cleanups are conducted on a “time-and-materials” (T&M) basis. Using the T&M basis, the contractor performs the work. Then the contractor bills for the hours worked and the cost of equipment and materials used during the work. With the T&M approach, spending for environmental cleanups by private and government entities has been difficult to contain. Also, actual contamination reduction has been slow.

The problem here is that some of the sentences are choppy and contain too little information, calling readers’ attention to how the sentences are constructed rather than to what the sentences say. In cases like this, the best way to revise is to combine sentences:

Customarily, environmental cleanups are conducted on a “time-and-materials” (T&M) basis: the contractor performs the work, then bills for the hours worked and the cost of equipment and materials. With the T&M approach, spending for environmental cleanups by private and government entities has been difficult to contain, and contamination reduction has been slow.

Another problem with excessively short sentences is that they needlessly repeat key terms. Again, consider combining sentences:

The conceptual, or “real,” subject of the sentence should also be the grammatical subject. Don’t disguise or bury the real subject in a prepositional phrase following a weak grammatical subject. In the following examples, the weak subjects obscure the real subjects. (The grammatical subjects are italicized.)

In revising a draft, look for the real subject (the topic) and ask yourself whether the sentence would be more effective if the real subject was also the grammatical subject. Sometimes all that is necessary is to ask yourself this question: What is the topic of this sentence? The author of the first example above wasn’t trying to say something about using a method; she was trying to say something about the method itself. Likewise, in the second example, it wasn’t the presence of a lactone ring that was detected; rather, the lactone ring itself was detected.

Another way to make the subject of the sentence prominent is to reduce the number of grammatical expletives. Expletives are words that serve a grammatical function in a sentence but have no meaning. The most common expletives are it (generally followed by is) and there (generally followed by is or are).

The second example uses the expletive it with the passive voice. The problem is that the sentence does not make clear who is doing the hoping.

Expletives are not errors. Rather, they are conversational expressions that can clarify meaning by emphasizing the information that follows them.

The second version is harder to understand because the reader has to remember a long subject (Whether the downturn will last more than a few months) before getting to the verb (is). Fortunately, you can revise the sentence in other ways to make it easier to understand and to eliminate the expletive.

I don’t know whether the downturn will last more than a few months.

Nobody knows whether the downturn will last more than a few months.

Use the search function of your word processor to locate both weak subjects (usually they precede the word of ) and expletives (search for it is, there is, and there are).

A “real” verb, like a “real” subject, should stand out in every sentence. A common problem in technical communication is the inappropriate use of a nominalized verb—a verb that has been changed into a noun, then coupled with a weaker verb. To install becomes to effect an installation; to analyze becomes to conduct an analysis. Notice how nominalizing the verbs makes the following sentences both awkward and unnecessarily long (the nominalized verbs are italicized).

Like expletives, nominalizations are not errors. In fact, many common nouns are nominalizations: maintenance, requirement, and analysis, for example. In addition, nominalizations often effectively summarize an idea from a previous sentence (in italics below).

The telephone-service provider decided not to replace the land lines that were damaged in the recent storm. This decision could prove a real problem for those residents who used land lines to connect to the Internet and for their medical-alert services.

Some software programs search for common nominalizations. With any word processor, however, you can identify most of them by searching for character strings such as tion, ment, sis, ence, ing, and ance, as well as the word of.

A sentence is parallel if its coordinate elements follow the same grammatical form: for example, all the clauses are either passive or active, all the verbs are either infinitives or participles, and so on. Parallel structure creates a recognizable pattern, making a sentence easier for the reader to follow. Nonparallel structure creates no such pattern, distracting and possibly confusing readers. In the following examples of nonparallel constructions, the verbs are not in the same form (verbs are italicized).

When using parallel constructions, make sure that parallel items in a series do not overlap, causing confusion or even changing the meaning of the sentence:

Modifiers are words, phrases, and clauses that describe other elements in the sentence. To make your meaning clear, you must indicate whether a modifier provides necessary information about the word or phrase it refers to (its antecedent) or whether it simply provides additional information. You must also clearly identify the antecedent—the element in the sentence that the modifier is describing or otherwise referring to.

Distinguish Between Restrictive and Nonrestrictive Modifiers As the term implies, a restrictive modifier restricts the meaning of its antecedent; it provides information that the reader needs to identify the antecedent and is, therefore, crucial to understanding the sentence. Notice that restrictive modifiers—italicized in the following examples—are not set off by commas:

The airplanes used in the exhibitions are slightly modified.

The modifying phrase used in the exhibitions identifies which airplanes the writer is referring to. Presumably, there are at least two groups of airplanes: those that are used in the exhibitions and those that are not. The restrictive modifier tells readers which of the two groups is being discussed.

Please disregard the notice you recently received from us.

The modifying phrase you recently received from us identifies which notice. Without it, the sentence could be referring to one of any number of notices.

In most cases, the restrictive modifier doesn’t require a relative pronoun, such as that, but you can choose to use the pronoun that (or who, for people):

Please disregard the notice that you recently received from us.

A nonrestrictive modifier does not restrict the meaning of its antecedent: the reader does not need the information to identify what the modifier is describing or referring to. If you omit the nonrestrictive modifier, the basic sentence retains its primary meaning.

The Hubble telescope, intended to answer fundamental questions about the origin of the universe, was last repaired in 2002.

Here, the basic sentence is The Hubble telescope was last repaired in 2002. Removing the modifier doesn’t change the meaning of the basic sentence.

If you use a relative pronoun with a nonrestrictive modifier, choose which (or who or whom for a person).

Go to the Registration Area, which is located on the second floor.

Use commas to separate a nonrestrictive modifier from the rest of the sentence. In the example about the Hubble telescope, a pair of commas encloses the nonrestrictive modifier and separates it from the rest of the sentence. In that respect, the commas function much like parentheses, indicating that the modifying information is parenthetical. In the example about the Registration Area, the comma indicates that the modifying information is tacked on at the end of the sentence as additional information.

Avoid Misplaced Modifiers The placement of the modifier often determines the meaning of the sentence, as the placement of only in the following sentences illustrates:

Only Turner received a cost-of-living increase last year.

Meaning: Nobody else received one.

Turner received only a cost-of-living increase last year.

Meaning: He didn’t receive a merit increase.

Turner received a cost-of-living increase only last year.

Meaning: He received a cost-of-living increase as recently as last year.

Turner received a cost-of-living increase last year only.

Meaning: He received a cost-of-living increase in no other year.

Misplaced modifiers—those that appear to modify the wrong antecedent—are a common problem. Usually, the best solution is to place the modifier as close as possible to its intended antecedent.

A squinting modifier falls ambiguously between two possible antecedents, so the reader cannot tell which one is being modified:

A subtle form of misplaced modification can also occur with correlative constructions, such as either . . . or, neither . . . nor, and not only . . . but also:

Here, the writer is implying that the refrigerant does at least two things to energy costs: it decreases them and then does something else to them. Unfortunately, that’s not how the sentence unfolds. The second thing the refrigerant does to energy costs never appears.

In the revised sentence, the phrase decreases not only implies that at least two things will be decreased, and as the sentence develops that turns out to be the case. Decreases applies to both energy costs and spoilage losses. Therefore, the first half of the correlative construction (not only) follows the verb (decreases). Note that if the sentence contains two different verbs, each half of the correlative construction precedes a verb:

The new refrigerant not only decreases energy costs but also reduces spoilage losses.

Avoid Dangling Modifiers A dangling modifier has no antecedent in the sentence and can therefore be unclear:

This sentence says that the instructions are trying to solve the problem. To correct the sentence, rewrite it, adding the clarifying information either within the modifier or next to it:

Sometimes you can correct a dangling modifier by switching from the indicative mood (a statement of fact) to the imperative mood (a request or command):