data: Style Guide Spelling Decisions (AP, Chicago, MLA, APA)

How major style guides rule on "data"

APA 7 still treats 'data' as plural ('data are'); AP and most journalism use it as a singular mass noun.

The disagreement on "data" is an example of singular vs plural treatment, the category of style-guide differences that most often confuses copy editors and creates inconsistency across long documents. Below is a guide-by-guide breakdown, drawn directly from the published editions cited.

What the divergence actually means

Unlike many compound-modernization decisions where style guides eventually converge, "data" continues to show genuine divergence between major guides. The AP Stylebook treats this as a settled call; Chicago Manual leaves more flexibility; and Merriam-Webster, as a descriptive dictionary, records both forms. Source: Chicago Manual of Style, 17th Edition

The APA Publication Manual diverges here: it specifies "plural" as the form preferred for academic writing in psychology and behavioral-science journals. APA's reasoning typically tracks scientific publishing conventions rather than newspaper-style economy. Source: APA Publication Manual, 7th Edition

Merriam-Webster lists "either", which serves as the lexicographic baseline for U.S. style decisions. Because Merriam-Webster's entries reflect aggregated published usage rather than editorial preference, when a guide says "follow Merriam-Webster", as APA does, that effectively delegates the call to whichever spelling has dominated the published corpus. Source: Merriam-Webster Dictionary

Garner's Modern English Usage classifies the "data (singular)" / "data (plural)" pair on its Language-Change Index, a five-stage scale measuring whether a once-disputed form has been accepted into Standard English. For singular vs plural treatment, Garner's typically rates the dominant form at Stage 4 ("ubiquitous but objected to by traditionalists") or Stage 5 ("fully accepted"). Source: Garner's Modern English Usage, 5th Edition

Practical guidance for editors

For working writers, the practical rule is straightforward: in journalism, follow AP; in academic writing in the humanities, follow MLA or Chicago; in social-science publishing, follow APA; in book publishing, follow Chicago. When no house style applies, Merriam-Webster's main entry is the safest default. The differences across these guides on "data" reflect not disagreement about correctness but different audiences and editorial pressures.

Editorial context

Evidence from Google Books N-grams charts a clear trajectory for data's number agreement, with the singular data is surpassing the plural data are around 1985, a pivot point after which singular usage accelerated in published English across diverse genres. This shift, accelerating amid the computing boom, reframes data from discrete Latin pluralia tantum akin to strata or phenomena toward an uncountable mass noun like metadata or feedback, mirroring how English absorbs foreign plurals into singular molds over time. By the 2000s, singular forms dominated even academic-adjacent texts, pressuring holdout styles despite etymological purism; for instance, The data suggests a correlation now reads as idiomatic in most registers, while The data suggest a correlation evokes formal science circa 1970. Such corpus trends guide editors toward singular for general audiences, prioritizing evolved usage over classical precedent.

Cross-references

For the dictionary entry, frequency data, and pronunciation of data, see the main word page. For other style-guide spelling decisions in this category, browse all style-guide spelling rulings.