When is it necessary to use a hyphen in writing a compound word?

Also use hyphens forCompounds in which the base word iscapitalized: pro-Freudiana number: post-1970an abbreviation: pre-UCS trialmore than one word: non-achievement-oriented studentsAll "self-" compounds whether they are adjectives or nounsself-reportself-esteemthe test was self-pacedDo not use a hyphen unless it serves a purpose. If a compound adjective cannot be misread or, as with many psychological terms, its meaning is established, a hyphen is not necessary. In a temporary compound that is used as an adjective before a noun, use a hyphen if the term can be misread or if the term expresses a single thought (i. e., all words together modify the noun).