When you follow[-]up with a follow[-]up letter, which follow up takes the hyphen?

To answer that question, let's talk about compounds. Not chemical compounds, but word compounds. They come in three varieties: spaced, hyphenated and solid.

Over time, their spelling tends to change. Compounds that were once spelled as spaced compounds (such as week end) become hyphenated compounds (week-end) and finally solid compounds (weekend). Curiously, however, certain compounds such as high school resist evolution. Go figure.

To make things particularly challenging for the harried writer, not all dictionaries agree on the preferred spelling of certain compounds. Sometimes their spelling differs even within the same industry. For example, Blue Cross provides health care and Mayo Clinic provides healthcare.

What's a conscientious writer to do?

First, ask yourself a simple question: Are you using the compound as a verb, an adjective or a noun? That's an important distinction, because the spelling of many compounds varies according to their use.

For example, the compounds in the opening sentence of this column should be spelled "Did you follow up with a follow-up letter?" The verb is spelled as a spaced compound, and the adjective (like the noun form) is spelled as a hyphenated compound.

Although some writers are now spelling the adjective and noun forms as followup, the preferred usage is follow-up, as in follow-up letter, not followup letter. Similarly, some dictionaries (as well as iPhones) are now spelling all right as a solid compound (alright), but careful (and cautious) writers continue to spell it as a spaced compound.

So what can you do to get it right?

After you have determined how you're using the compound (as a verb, adjective or noun), look it up; don't guess. If you're using a hardcopy dictionary, make sure it's a current edition. If you're using an online dictionary, make sure it's reliable. Sometimes simply googling the compound will indicate consensus spelling, but you still need to know how the compound is being used.

Here are three helpful patterns to keep in mind:

1. When a compound adjective precedes the word it modifies, it usually takes a hyphen ("You do first-rate work"), and when it follows the word it modifies, it usually doesn't ("Your work is first rate").

2. Compounds used as verbs are generally spelled as two words (as in to log on and to set up).

3. Certain compound verbs (such as to double-space, to spot-check and to under-report), however, take a hyphen.

In addition to follow up/follow-up, the following compounds are commonly misspelled: follow through, set up, log in, sign in, check in and check out.

With these patterns and commonly misspelled compounds in mind, correct the errors in the following sentence: "Be sure to spot check for problems before you logon and set-up your program according to the set-up instructions."

The correct spellings are spot-check, log on, set up and setup (but follow the logon instructions).

When your sources disagree, avoid both the vanguard (alright) and the rearguard (co-operate). Aim for the safe middle ground. For guidance in spelling some 700 common compounds, google "Wilbers compounds."

Stephen Wilbers offers training seminars in effective business writing. E-mail him at wilbe004@umn.edu. His website is www.wilbers.com.