Hyphens have two main purposes. One is to join words together, while the second is to separate the syllables in words. When we are writing our technical research papers, we are generally involved in the first use. Let’s see if we can apply some rules to how hyphens should be used (understanding that there is actually not one such set upon which we can draw. Different style manuals may offer slightly different recommendations for use. Also, rules may differ on a country-by-country basis. Hey, look, two hyphens in one term!).
Let me start by offering one of the most commonly misused terms I see in our combined writing. Look at the following term:
High velocity low amplitude manipulation
Because we understand the context, we know what the terms means. But let’s say you have no knowledge of chiropractic technique. What words here modify what other words? Does the word “velocity” modify the word “low?” In fact, as written we cannot make sense of the term, since we have no way to know which words are modifying other words. Hyphenation makes this all understandable:
High-velocity low-amplitude manipulation
It is now clear that “high” modifies “velocity” and “low” modifies “amplitude” and both combined terms then modify “manipulation.”
1. There are no spaces between the hyphen and the words it connects.
2. Numbers below 100 are hyphenated, i.e. thirty-five
3. Hyphens are important in compound modifiers. This was the example I gave above, but let’s look at one more: “American football player.” Now, look at this and answer if you can tell whether or not we are referring to (1) an American who is a football player, or (2) an athlete who plays American football. You cannot tell. If this were written as “American-football player,” it is now clear that you are referring to someone who plays American football. If we look at the term “high ranking official,” it is not clear whether the we are referring to an official of high ranking, or a ranking official who is, uh, high. J
I always ask myself, is a term confusing? Using a term closer to home, what do I do with “cross country runner?” Is there an angry country runner or is there a runner who runs cross country? The proper term is cross-country runner. Wikipedia offers an interesting one: “man eating shark.” Without hyphenation, this really means that a man is eating shark (probably at a restaurant!), while man-eating shark is eating you (probably in the ocean…). Hyphens matter in making text understandable!