Each of the following sentences below demonstrates a specific type of error involving internal punctuation, usually involving a problem with a comma. Discussion and revision following each example explains and illustrates correct use of punctuation in the sentence.
1. Misplaced Punctuation
This approach requires an effective model risk governance program, and crucially, validation of the model by an independent party.
A comma is needed after program only if what follows is an independent clause. In this case, the rest of the sentence is merely the rest of an extended compound predicate. However, crucially is a parenthetical, and a comma is required before as well as after it: “This approach requires an effective model risk governance program and, crucially, validation of the model by an independent party.”
2. Missing Punctuation
Specifically her portfolio did not include the required number of samples.
An adverbial introduction must be set off from the main clause by a comma: “Specifically, her portfolio did not include the required number of samples.”
3. Unpaired Punctuation
The survey found increasing demand for customer experiences that are difficult, if not impossible to deliver with legacy systems.
Related to the misplaced and missing examples above, this sentence is flawed in that the parenthetical phrase “if not impossible” is set off only in front, not behind as well: “The survey found increasing demand for customer experiences that are difficult, if not impossible, to deliver with legacy systems.”
4. Extraneous Punctuation
Knowing which sensitive data need to be highly protected, where this information sits within the organization, and what security mechanisms need to be applied, are all key considerations for a sound information security risk assessment.
A comma should not precede a verb unless it is the second of two commas bracketing a parenthetical phrase: “Knowing which sensitive data need to be highly protected, where this information sits within the organization, and what security mechanisms need to be applied are all key considerations for a sound information security risk assessment.”
5. Excessive Punctuation
Consumers have the right to speak out or complain, and to seek compensation—payment or a replacement item—or redress—have a wrong corrected.
Excessive punctuation often occurs when a sentence is cluttered with commas, and a sentence should be recast or divided into two or more sentences if more than a few commas appear (and semicolons are not included to assist in sentence organization). But when dashes are used to set off parenthetical phrases, no more than one pair should be used, because readers may have difficulty at first recognizing which parts of the sentence are being bracketed. Either revise the sentence so that only one pair of dashes is needed, or replace dashes with parentheses, which because the open and close parentheses are shaped differently, clearly indicate what is contained within them: “Consumers have the right to speak out or complain and to seek compensation (payment or a replacement item) or redress (have a wrong corrected).” (Note, too, that the sole comma is superfluous.)
6. Inconsistent Punctuation
Last year a man agreed to give up his drone system and promise not to fly a drone for three years. . . . Last month, the FAA announced there are now more registered drone operators in the United States than there are registered manned aircraft.
If an optional punctuation mark is used in one sentence in a piece of content, it should be used in any similarly constructed sentence; see the consistent inclusion of a comma after the short introductory phrase in both sentences: “Last year, a man agreed to give up his drone system and promise not to fly a drone for three years. . . . Last month, the FAA announced there are now more registered drone operators in the United States than there are registered manned aircraft.” (Note that “last year” and “last” month serve the same adverbial function as specifically in the second example, but such brief introductory phrases do not require punctuation, though for consistency, it is recommended.)
7. Incorrect Punctuation
One person had to be airlifted off the site after the structure collapsed Monday night, the rest were treated at an on-site medical facility.
Because this sentence consists of two independent clauses, they must be separated by a semicolon rather than a mere comma: “One person had to be airlifted off the site after the structure collapsed Monday night; the rest were treated at an on-site medical facility.” (A period is also appropriate, but the close relationship of the two clauses allows for a semicolon.)
I’d say the most common mistake I see is #3, unpaired punctuation. I see it all the time in simple sentences like this: He was born in Bryn Mawr, Pa. in 1990.
Note: “7. Incorrect Punctuation”
“One person had to be airlifted off the site after the structure collapsed Monday night, the rest were treated at an on-site medical facility.”
This is called a “comma splice”, and it is a Big Nasty.
On the other hand, a lot of writers from the former British Empire do not see it that way. They are wrong, of course.
Comma splices are worse than SPECTRE, SMERSH, and THRUSH, and just as insidious!
Notice that “This is called a ‘comma splice’, and it is a Big Nasty,” consists of two independent clauses, joined together properly with “and”.