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Grammar

Six errors account for most of what we mark in academic drafts

Not the exotic ones. These are the errors that survive a spellchecker, sound fine when read quickly, and get flagged by graders because they make a sentence say something other than what was meant.

3 min read · Last reviewed September 2026

Common questions

Frequently Asked Questions

Traditionally plural, with datum as the singular, so the data were collected. In practice many disciplines now accept the singular, and APA prefers the plural. Check your field's convention and, more importantly, be consistent within the document. Switching between the two in one paper is what gets graded.

An opening phrase that describes something the sentence never names. After analyzing the data, the results were surprising implies the results did the analyzing. Fix it by naming the actor at the start of the main clause, as in after analyzing the data, we found the results surprising.

Broadly: past tense for what you did and what previous studies found, present tense for established knowledge and for what your tables show, and present or future for what your findings imply. The literature review is usually past or present perfect, and results are past.

In most disciplines now, yes, and APA explicitly prefers first person to awkward constructions like the researcher. Some fields and some instructors still prohibit it, so check. Avoid the passive voice used purely to dodge the question, because it usually makes the sentence harder to read.

Affect is usually the verb, meaning to influence. Effect is usually the noun, meaning the result. The intervention affected the outcome, producing a measurable effect. Effect can be a verb meaning to bring about, as in to effect change, which is rare and often mistaken for the other one.

In American usage, that introduces essential information and takes no commas, while which introduces nonessential information and takes commas. The instruments that failed calibration were replaced identifies which instruments. The instruments, which failed calibration, were replaced says all of them failed.

Partly. It reliably catches agreement and some punctuation. It is much weaker on dangling modifiers, ambiguous pronoun reference and tense consistency across a long document, because all three need an understanding of what you meant rather than of what you typed.

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