Job Interview

All could be correct. My feeling:

in = participating

on = conducting

at = being interviewed

Others may have other interpretations.

All are correct. The meaning will depend on the context.

For example, if you are talking about a friend then any of these would mean the he was being interviewed. If a receptionist is explaining why someone was not available she might say, "Mr. xyz was in an interview." meaning he was conducting an interview with a potential employee. The variations are too numerous to attempt to describe

Another example:

"'Good teachers will contribute to the success of our students,' said the school principal in/at/on a interview with reporters."

Would "in", "at", and "on" be all equally acceptable?

MeggPhaggSioux'Good teachers will contribute to the success of our students,' said the school principal in/at/on a interview with reporters."

With a context of a reporter, "during" is the best choice in my assessment.

So,

"He will be in a job interview."
"He will be at a job interview."
"He will be on a job interview."

are wrong?

So,

"He will be in a job interview."
"He will be at a job interview."
"He will be on a job interview."

are wrong?

Go back to review Phillip's and MalRay's explanatons carefully. Each preposition carries an implied meaning.

It seems that,

"He will be on a job interview."

is the most contraversial. I find this in Washington Post:

"After you have been on an interview or two with an employer, however, you can diminish you

This is what I can't understand. You keep quoting from known good sources but question the author's use of the language. We can't possibly answer every excerpt from your quote. This is not a job seeking forum.

MeggPhaggSiouxWhat do you think?

That's a loaded question.