Statistical copy is the most technically demanding element of APA 7th formatting, and the errors that accumulate in it are among the most resistant to correction by authors working alone. The rules are specific. The manual distributes its treatment of them across multiple sections, and the conventions that feel intuitive — about when to italicize, when to use abbreviations, how to handle spaces around operators — frequently turn out to be wrong.
Italicization of statistical symbols. APA 7th requires that most statistical symbols be italicized when they appear in text. This includes the common inferential statistics — t, F, r, p, M, SD, N, n, df. Greek letters used as statistical symbols, such as α, β, and χ, are set in regular type. Inconsistency is the usual failure. Authors italicize in some instances and not others within the same document, or apply italics to symbols that do not require them.
Spacing around operators and values. APA 7th requires a space on both sides of mathematical operators and comparison symbols when they appear in running text. The correct form is p = .043, not p=.043. The same rule applies to test statistics and to inequality symbols: t(38) = 2.14, not t(38)=2.14, and p < .001, not p<.001. Missing spaces around operators are among the most common statistical formatting errors in dissertations, and among the easiest to correct. A targeted find-and-replace pass fixes them.
Reporting of exact p values. APA 7th no longer recommends reporting p values as inequalities (p < .05) except when the value falls below .001, in which case it is reported as p < .001. For all other values, the exact p value should be reported to three decimal places: p = .043, p = .127. Authors trained in APA 6th conventions frequently continue to report inequality forms for all values, unaware that this convention changed in the 7th edition.
Leading zeros. APA 7th does not use a leading zero before the decimal point for values that cannot exceed 1.0 — including p values, correlation coefficients, and effect sizes expressed as proportions. The correct form is p = .043, not p = 0.043. For values that can exceed 1.0, the leading zero is used. The distinction is simple once stated. It is reliably missed in practice.
Effect size reporting. APA 7th requires that effect sizes be reported alongside inferential statistics for all primary analyses. The specific effect size measure should be appropriate to the statistical test — Cohen's d for mean comparisons, r or r² for correlations, η² or partial η² for ANOVA designs — and should be reported with its confidence interval where feasible. Omitting effect sizes is a formatting error under APA 7th. Reviewers count it as a methodological gap.
Sample size notation. Italicized N refers to the total sample. Italicized n refers to a subsample. The two are not interchangeable, and their incorrect use, particularly N where n is required, appears regularly in the results sections of dissertations.
Meeting the APA 7th standard for statistical copy takes a format-specific review pass, separate from the substantive editing of the document.
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