3 Cases of Misuse of Dashes

In each of the following sentences, dashes are erroneously employed, resulted in confused sentences. Discussion following each example explains the problem, and one or more revisions illustrate solutions.

1. When driving long distances—know that children get restless.

A dash is not applicable when one clause naturally follows another. “Know that children get restless” does not abruptly break from the subordinate clause that precedes it, so a comma suffices here: “When driving long distances, know that children get restless.”

2. Few banks can afford their customer experiences to plateau for long before customers with ever-increasing expectations choose to do business with a competitor—or worse—with a disruptive market entrant.

“Or worse” is treated here as a parenthetical phrase but is not intended as one. Because what follows the first dash signals a syntactical break, only that first dash is called for. In addition, because worse, on its own, is parenthetical to the phrase “or with a disruptive market tenant,” it should be bracketed by punctuation, but two mere commas suffice (and a pair of dashes would confuse in proximity to the preceding one): “Few banks can afford their customer experiences to plateau for long before customers with ever-increasing expectations choose to do business with a competitor—or, worse, with a disruptive market entrant.”

3. Some features predicted in this article—like seat belts—became ubiquitous, while others—like braking distance indicated on speedometers—never caught on.

As mentioned in the discussion for the previous example, employing one or two dashes more than once in a given sentence can be confusing, as readers see several phrases separated by the dashes with no indication of syntactical hierarchy, so avoid doing so: “Some features predicted in this article, like seat belts, became ubiquitous, while others, like braking distance indicated on speedometers, never caught on.”

If two complementary phrases, such as those specifying examples in the original sentence, are going to be used parenthetically, the pairs of punctuation marks must be identical to indicate their equivalence. However, in this case, because a comma already exists in the sentence, the sentence organization is still muddled (and the statement is crowded with commas), so it is more helpful to the reader to frame the two examples in parentheses: “Some features predicted in this article (like seat belts) became ubiquitous, while others (like braking distance indicated on speedometers) never caught on.”