Omission of a lowly comma often alters the intent of a sentence, as demonstrated in the following examples, each followed by discussion and a revision.
1. Customers likely to be the target of any kind of prosecution under this law include individuals who use tax planners such as celebrities and politicians.
This sentence mistakenly implies that celebrities and politicians sometimes double as tax planners, but the terms for those classes of people are modifying individuals, not “tax planners,” so either relocate the pertinent phrase “such as celebrities and politicians” to follow individuals, or simply set the phrase off with a comma: “Customers likely to be the target of any kind of prosecution under this law include individuals who use tax planners, such as celebrities and politicians.”
2. Within three years, the company projects that 67 percent of all spending on enterprise information technology will target cloud-based products and services.
Omission of a comma to complement the one preceding what should be a parenthetical phrase leads to the erroneous implication that the projection is directly tied to the period specified. But “the company projects” is merely an attribution, and “within three years” pertains to the percentage figure, not the projection: “Within three years, the company projects, 67 percent of all spending on enterprise information technology will target cloud-based products and services.” (Note also the deletion of that.)
3. Organizational structure does not specifically represent a building block of procurement success—at least not in the way that cost analysis, sourcing or savings methodology and tracking do.
Does this sentence refer to cost analysis, sourcing, and savings methodology and tracking, or does it refer to cost analysis, sourcing or savings methodology, and tracking? The context may be clear for experts, but a layperson may be perplexed, and even someone very familiar with these concepts may be momentarily puzzled. If your publication does not customarily employ serial commas, use one nevertheless when one or more items in an in-line list (one appearing within a sentence) is complex (“a and b”). Better yet, always use the serial comma: “Organizational structure does not specifically represent a building block of procurement success—at least not in the way that cost analysis, sourcing, or savings methodology and tracking do.”
Two thumbs up for the serial comma!
The serial comma can reduce the potential for misunderstanding. On the other hand, inconsistent use of the serial comma can increase the potential for misunderstanding. For these two reasons, I advocate for its use in all series. If our goal is clarity, we lose nothing and potentially gain much by using the serial comma in all cases.