Four of these pet peeves were suggested by readers in response to my April e-letter, Write This, Not That. If your favorite doesn’t appear in either list, send it along!

1. Imply vs. infer

Some people use infer as if it were interchangeable with imply.  Actually, they are opposites, in the sense that speak and hear are opposites. To imply is to suggest or say indirectly. To infer is to draw a conclusion.

NO A correlation between colorful clothing and inappropriate behavior was inferred by the report.

(I see this mistake in the passive voice more often than in the active. Reason #965 not to use passive voice when an active alternative is available.)

YES The report implied that wearing colorful clothing correlates with inappropriate behavior.

YES  We inferred from the report that people should always wear black so they will act appropriately.

How to get it right
Writers (or speakers) imply. Readers (or listeners) infer. It’s as simple as that. No overlap.

(An aside that has nothing to do with grammar but quite a lot to do with precision: The YES examples illustrate the fact that a reader or listener may well infer something that the writer or speaker did not in fact imply. Political pundits and students of literature or sacred texts, take note.)

2. Who that?

Who refers to people, and that refers to things. We know this, right? Yet often I see sentences like this:

NO Students that infer ideas not found in the text will fail the exam.

Last I checked, students were still people.

YES  Students who infer ideas not found in the text will fail the exam.

What about corporate entities? Is a company, a staff, or a congregation – each of which, after all, comprises people – a who or a that? Citizens United notwithstanding, such groups of persons are treated grammatically as things.

YES  The organization that empowers its staff sets itself up for success in initiating change.

How to get it right
Are you talking about people? Then use who. The opposite mistake, saying who when you mean that, is rare, so don’t worry about it.

3. That which confuses

Some people who genuinely care about writing correctly are flummoxed by the choice between that and which.

NO The organization which empowers its staff sets itself up for success in initiating change.

NO Strictly hierarchical organizations, that may be either for-profit or nonprofit, are often resistant to change.

Leaving out all the fancy grammatical terms makes the issue pretty simple. Try reading the sentences above without their that/which clauses.

The organization … sets itself up for success in initiating change.

Huh? Which organization are you talking about? Oh, the one that empowers its staff. If the sentence needs the relative clause in order to make sense, use that.

Strictly hierarchical organizations … are often resistant to change.

This sentence makes sense without the clause. The fact that these strictly hierarchical organizations can be for-profit or nonprofit is interesting but not necessary information. In that case, use which, with commas before and after the clause.

How to get it right
If you can leave out the information in the clause, use which with commas. If not, use that with no commas.

4. Within / in, upon / on

I wish I had a nickel for every within I’ve edited down to in and for every upon I’ve edited to on. Within and upon both have specific meanings.

Within means “inside certain boundaries.” Use it to suggest enclosure – inside a thing when speaking concretely, or inside a range when speaking abstractly.

YES We will give you feedback within three days.

“Within three days” establishes a range. We might give you feedback in one day, two days, or three days. If we said “in three days,” then you would expect feedback on the third day.

NO We studied attitudes toward change within nonprofit organizations.

There’s no range here. Use in instead of within.

YES We studied attitudes toward change in nonprofit organizations.

Similarly, people seem to use upon because it sounds fancier than on. Upon means “on top of.” If that’s not what you mean, use on.

NO Upon learning that their organization was going to require them to wear colorful clothing, the employees revolted.

YES They piled one argument upon another.

In the second case, you could substitute “on top of,” so upon is correct – though even there, on would be perfectly acceptable. In the first case, however, there’s nothing for anything else to be on top of. Use of on would be less stilted.

How to get it right
Every time you start to write within, try to substitute in. Every time you start to write upon, try to substitute on. If you can, do.

5. i.e. or e.g.

People often confuse i.e. – an abbreviation for the Latin id est, meaning approximately “that is” – and e.g., an abbreviation for the Latin exempli gratia, meaning approximately “for example.”

NO  The analysis focused on quantitative methods (i.e. random control trial) rather than qualitative methods (i.e., case study).

This writer meant e.g., “for example,” rather than i.e., “that is.” The sentence gives one example each of a quantitative and a qualitative method.

How to get it right
Eschew Latin abbreviations. Stick to good old English “for example” and “that is,” and you will never get confused.

Another way to get it right
Hire someone who knows.