Agreement Flags in a Chemistry Lab Report
A student's lab report contains four sentences: "Each of the water samples were tested twice. The set of measurements from the second trial show a wider spread than the first. Neither the instructor nor the lab assistants was able to reproduce the outlier. Finally, a researcher should always record their procedure in real time." The instructor marked four agreement problems. The student pushes back: "'were' sounds right because 'samples' is plural, and 'their' is fine because everyone says it." The report is for a formal chemistry course whose syllabus states that written work follows conventional academic grammar.
1. Explain why "Each of the water samples were tested" is incorrect and give the corrected verb. Address the student's "it sounds plural" reasoning.
Read the worked answer
The subject is each, not samples. Each is a singular indefinite pronoun, so the verb must be singular: "Each of the water samples was tested twice."
The phrase of the water samples is a prepositional phrase. Prepositional phrases never supply the subject of a sentence; they only modify it. The student's ear is reacting to samples, the noun sitting closest to the verb - a very common trap, because English speakers are drawn to the nearest noun. The grammar, however, tracks the headword of the subject.
A quick self-check the student can reuse: strip the prepositional phrase. "Each ... was tested twice" is obviously correct; "Each ... were tested" is obviously not.
2. "Neither the instructor nor the lab assistants was able to reproduce the outlier." Is the verb correct? State the rule you are applying.
Read the worked answer
Incorrect as written; it should be "were."
With a neither ... nor (or either ... or) construction, the verb agrees with the subject closer to it - here, the lab assistants, which is plural. Hence "Neither the instructor nor the lab assistants were able to reproduce the outlier."
Note how the rule behaves if the elements change: "Neither the instructor nor the technician was able..." would be correct, because the nearer subject is singular. This is why the construction must be checked case by case rather than memorized as "neither is always singular."
If the mixed construction feels awkward, the writer can recast: "The instructor and the lab assistants were unable to reproduce the outlier." That is a legitimate stylistic escape when the nearer-subject rule produces a sentence the writer keeps stumbling over.
3. Evaluate "a researcher should always record their procedure in real time." Is this an error? How should the writer decide in this course?
Read the worked answer
It is not a grammatical error in current usage, but it is a style risk in this specific setting.
Singular they/their after an indefinite noun (a researcher) is long-established and widely accepted in published academic and journalistic prose. A blanket "this is wrong" would be inaccurate.
However, the syllabus here commits the writer to conventional academic grammar, and some instructors still mark singular their as an agreement error. The writer has three options:
- Recast to plural - "Researchers should always record their procedures in real time." This removes the disagreement question entirely, changes no meaning, and reads naturally. Best choice.
- Use his or her - formally defensible but clunky, and it assumes a binary.
- Keep their - acceptable if the instructor's rubric allows it, but the writer should not gamble on that without asking.
The judgment principle: when a usage is disputed rather than wrong, prefer the revision that no reader will object to.