Punctuation tip: Using apostrophes, Part III

So far, we've addressed using apostrophes in possessives and in contractions. Those usages can be tricky at times, but generally (with the exception of its/it's, which is a perennial problem), the rules are well understood. This week, all that changes. One class of apostrophes is truly strange.

Certain Plurals
Some plural usages just don't fit into traditional categories and require special treatment. However, let's first address a group of plurals that, though we are often tempted to do so, should NOT be treated any differently: numerals and year groups. The three sentences below are correct as written.

The accountant found the problem: There were two Entry 12s.
Sandra ended her first career in the late 1980s.
The first dozen phone numbers in the database were 212s.

I repeat: These sentences are correct and DO NOT require the addition of apostrophes. But if the apostrophe-less numbers just don't look right to your eye, and you're willing to put in a little extra brainwork and finesse to work around them, you have options. One is to write the numerals out as words. This works better in some sentences than others:

Sandra ended her first career in the late nineteen-eighties. [reasonable]
The first dozen phone numbers in the database were two-one-twos. [awkward since words can't be "dialed" effectively]

There's another option also. Sometimes a sentence can be comfortably recast to avoid pluralizing at all.

The accountant found the problem: Entry 12 appeared twice.
By 1990, Sandra had ended her first career.
The first dozen phone numbers in the database were from the same area code, 212.

So what's the bottom line? Don't add an apostrophe to something just because it represents a number. Most respected style guides, including The Chicago Manual of Style and the AP Style Guide, agree this is the best practice. Celebrate the simplicity!

Pluralizing letters, unfortunately, isn't quite as straightforward. There are four conditions you must consider to make an accurate judgment about whether to use an apostrophe.

Rule 1: For lower-case stand-alone letters, use an apostrophe to separate the letter and its pluralizing s.

The broken keyboard resulted in documents full of unnecessary c's and x's.
His speech impediment caused him to pronounce his s's more like z's.

Rule 2: For abbreviations consisting of all capital letters, use a lower-case s and NO apostrophe to pluralize.

Susan and Philip both contributed regularly to their IRAs.
The URLs in question all belong to the same corporation.
Janie knew her ABCs by the time she was one year old.

Chicago, AP, and many other respected guides follow Rules 1 and 2 above, which means most plural-apostrophizing (Did I just coin a word?) choices are simple. For Rule 3, the authorities part ways.

Rule 3: For some capital letters, use an apostrophe before the pluralizing s.

Chicago rule: Every curriculum in this school district is based on the three Rs.
AP rule: Every curriculum in this school district is based on the three R's.

The key for correctly applying Rule 3, then, is to know whether the person or organization for whom you are writing has a style preference. If so, go with that. Otherwise, either usage is justifiable as long as you use it consistently.

And finally, as an editor, I would also add one more rule. This is my recommendation based on a combination of stated Chicago and AP standards, their underlying reasoning, and a little logic from a reader's perspective.

Rule 4: For abbreviations that consist of mixed upper- and lower-case letters and/or internal periods, use an apostrophe to separate letters and pluralizing s where reasonable. However, to avoid awkward constructions and misreading, recasting is sometimes preferable to using a plural at all.

In 2009, the university graduated forty-six M.A.'s.

This sentence would look better in print recast thus:

In 2009, the university graduated forty-six Master of Arts students.

However, in some cases, sticking to the abbreviations, even with all their clunky punctuation, is a far more efficient choice.

The university's 2009 graduating class included forty-six M.A.'s, twenty-one Ed.D.'s, and twelve Ph.D's.

The slim sentence above is certainly preferable to this wordy mess:

Among the university's 2009 graduating class were forty-six recipients of Masters degrees, twenty-one doctorates in education, and twelve doctorates in philosophy.

As this is the final post in my apostrophes series, I'm especially interested in any questions you have about examples or exceptions that I have not specifically addressed. But, as always, all other comments are welcome also. Have at it!