When commas are employed to set off a break in thought, or are used to set off more than two distinct sentence elements, the result is often a flat or confusing sentence. To properly signal an abrupt syntactical change or clearly indicate syntactical hierarchy, consider replacing one or two commas with a dash or two, as described in a discussion and shown in a revision following each of the examples in this post.
1. When issues strike unexpectedly, and they will, the head of the department can expect to engage in swift troubleshooting discussions.
The bracketing commas are not incorrect, but they’re lackluster and ineffectual in emphasizing the point of the key interjection; dashes are more successful: “When issues strike unexpectedly—and they will—the head of the department can expect to engage in swift troubleshooting discussions.”
2. The disclosure of data, even, or especially, to law enforcement, is a hot topic.
In this case, the reader will likely have to backtrack to diagram this sentence in his or her mind to process that “data, even, or especially” is not a list and that even is the beginning of a two-layer parenthesis; frame the outer parenthesis with dashes to distinguish it from the inner parenthesis: “The disclosure of data—even, or especially, to law enforcement—is a hot topic.”
3. When you write for a newspaper, you actually can change the world, well at least a corner of it, for some people.
The problem here is similar to that of the previous example, in that well must be set off from the rest of the parenthesis of which it is a part. To distinguish between the punctuation used to do so and the punctuation employed to emphasize the parenthesis itself, promote the quotidian commas to distinctive dashes: “When you write for a newspaper, you actually can change the world—well, at least a corner of it—for some people.”