Should FixStyleFound in 1-2% of dissertations

Numbers Under Ten: The APA Rule That Catches Every Dissertation Writer

Found in 1-2% of dissertations we analyze. APA requires you to spell out numbers below 10 — writing "3 participants" instead of "three participants" is a formatting error your committee will flag.

FIX

Spell out this number as a word.

What This Issue Is

APA 7th edition has a clear baseline rule: spell out numbers zero through nine; use numerals for 10 and above. So it's "three studies," "seven participants," and "nine categories" — but "10 schools," "23 respondents," and "147 survey items." This rule applies throughout your text, tables, and figures unless a specific exception applies.

The exceptions are where writers get tripped up. Use numerals regardless of size when the number: precedes a unit of measurement (5 cm, 3 mg), represents a statistical or mathematical value (a factor of 3), appears in a table or figure, represents time, dates, ages, or scores, or appears with a number 10 or above in the same sentence referencing the same category ("between 3 and 15 sessions").

Committee members flag this consistently because it's objectively right or wrong — there's no judgment call. Either you spelled out "three" or you wrote "3." This makes it a favorite target for form-and-style reviewers who can check it mechanically. The fix is equally mechanical: search your document for single digits and apply the rule.

Why Your Committee Flags It

Writing "5" instead of "five" violates APA guidelines. While minor, these errors accumulate and suggest insufficient attention to formatting requirements.

Before & After Examples

Before

Participants completed 4 sessions over 6 weeks.

After

Participants completed four sessions over six weeks.

Numbers under 10 must be spelled out in running text.

Before

The study included 3 schools and 7 classrooms.

After

The study included three schools and seven classrooms.

"Two" is correct (under 10). Time with units uses numerals.

Before

Participants completed the survey in two sessions lasting 45 minutes each.

After

Participants completed the survey in two sessions lasting 45 min each.

When comparing numbers in the same category and one is 10+, use numerals for both.

Before

There were nine items in Group A and 12 items in Group B.

After

There were 9 items in Group A and 12 items in Group B.

Self-Check Checklist

Tap each item as you review your chapter.

Related Checks

Must Fix

Citation Format (comma required)

5-10% of dissertations

Should Fix

Ampersand Usage (& in parentheses)

2-4% of dissertations

Must Fix

Et Al. Format

2-3% of dissertations

Must Fix

Stray Punctuation

1-2% of dissertations

Should Fix

Informal Language

2-3% of dissertations

Frequently Asked Questions

The base rule: spell out zero through nine, use numerals for 10 and above. Exceptions requiring numerals: before measurement units (5 cm), statistical values, ages, times, dates, scores, and when comparing numbers in the same category where any number is 10+. Numbers at the start of a sentence are always spelled out.
Always spell it out, even if it's above 10: "Twenty-three participants completed the study." If the number is large or awkward to spell out, restructure the sentence: instead of "One hundred forty-seven students were surveyed," write "The survey included 147 students."
Tables and figures always use numerals for clarity and space. The spell-out-under-10 rule applies to running text (body paragraphs). However, when you reference a table or figure number in text, use numerals: "see Table 3" and "Figure 2 shows."
Yes. MLA spells out numbers expressible in one or two words ("twenty-one" but "101"). Chicago spells out numbers zero through one hundred. APA's under-10 rule is the strictest threshold. Make sure you're following the correct style guide for your program.

Sources

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