Academic Guides: Grammar and Mechanics: Hyphens

Hyphen Basics

A hyphen is a punctuation mark that connects words.

Example: The peer-reviewed research suggested...

Example: As a fourth-grade teacher, I...

Example: Anderson (1998) tried to avoid face-to-face conflicts.

Review APA 7, Sections 6.11 and 6.12 as well as Tables 6.1, 6.2, and 6.3 for more detailed hyphen guidelines.

If a temporary compound can be misread.
- “Adolescents resided in two parent homes” (APA 7, p. 162). For clarity, this can be rewritten as, “Adolescents resided in two-parent homes.”
When there is a compound with a participle (i.e., verb ending in –ed or –ing) that precedes the term it modifies
- evidence-based practice
When an adjective-and-noun compound precedes the term it modifies
- low-income families
When a compound has a number as the first element and the compound precedes the term it modifies
- 10^th-grade students
When a fraction is used as an adjective
- one-fourth minority
When two or more compound modifiers have a common base
- long- and short-term memory
When the base word in the compound is capitalized
- Likert-type scale
When the base word is a number
- pre-2010
When the base word is an abbreviation
- pre-CDC recommendation
When the base word is composed of more than one word
- non-peer-reviewed research
When “self” is used as the compound
- self-report
When words could be misunderstood
- re-pair (to pair again)
When the prefix ends and the base word begins with “a,” “i,” or “o”
- meta-analysis
- co-occur

When the compound follows the word it modifies.
- Incorrect: The research was peer-reviewed.
- Correct: The peer-reviewed research...
With compound adjectives when they cannot be misread or when their meaning is established (a permanent compound)
- health care reform
With compounds including an adverb endling in “-ly”
- widely distributed information
With compounds including a comparative or superlative
- higher order learning
With chemical terms
- biochemical oxygen demand
With Latin phrases use as adjectives or adverbs
- post hoc test
With modifiers including a letter or numeral as the second element
- Type II diabetes
With fractions used as nouns
- three fourths of the participants
With prefixes “pre” and “re” when the base word begins with an “e”
- preexisting
- reexamine
With most prefixes and suffixes.
- The unbiased study displayed multifaceted information about agoraphobia.

Here is a list of prefixes and suffixes that do not require hyphens (taken from APA 7, Table 6.2):