Many people disagree about which words to hyphenate. Is it macro-economics or macroeconomics (or even macro economics)? Should one say export-led or export led demand?
This is partly a matter of taste. The best advice here is to do what your reader would expect. If your lecturers have the habit of using a hyphen for a particular word(s), you should do so too. (When you have graduated, you can do as you want. In the meantime, keep your teachers happy.) It is also an area where different house rules make different decisions.
It is also a matter of how the writer sees the chosen word(s) - are they a unit or not? If they are a unit, try them as one word, without even a hyphen. If they are nearly one word, use a hyphen. If they are clearly two words, don't use a hyphen. In this context, it is worth noting that some pairs of words may be hyphenated when being used as one word class, but not when used in a different grammatical structure. For example, write on line as two words when you are using it adverbially (after a verb), as in "go on line", or "I found it on line"; but when you are using it adjectivally (before a noun), hyphenate it it: "an on-line source".
On 21st September 2007, on the publication of the 6th edition of The Shorter Oxford English Dictionary, Reuters filed a report on a changing attitude towards apostrophes entitled "Thousands of hyphens perish as English marches on". See it at []. The examples quoted in the article were:
Formerly hyphenated words split in two:
- fig leaf
- hobby horse
- ice cream
- pin money
- pot belly
- test tube
- water bed
Formerly hyphenated words unified in one:
- bumblebee - see also insect hyphenation
::You may also want to see keeper or -keeper.