Difference between “assist in” and “assist with”

Question

He assisted in the editing of the movie.

He assisted with the editing of the movie.

He assisted at the editing of the movie.

Is "assist in" the same as "assist with"? Can I always substitute the one where the other is used, or is there a difference in meaning?

(I think "assist at" refers to a place where a person is assisting, as in "He assisted at the place where the editing was taking place".)

Edit

When I use Google to look for the definition, it gives me the following as the main definition:

help (someone), typically by doing a share of the work

And gives two example sentences:

"a senior academic would assist him in his work"

and, after a bullet point with the following extra explanation:

• help by providing money or information.

"they were assisting police with their inquiries"

So is the distinction between in and with really tied to the definitions above, or are these example sentences just a coincidence?

Answer 1

Is "assist in" the same as "assist with"? Can I always substitute the one where the other is used, or is there a difference in meaning?

In general, they're pretty similar and frequently interchangeable -- at least one-way. (You can say "assist with" for "assist in," but you should be careful swapping "assist in" for "assist with," since there are some nuances.

If you "assist in," it may indicate a longer-term and/or more in-depth assistance -- the senior academic meeting with the junior one daily over a course of months, for instance.

If you "assist with" something, it can indicate a much shorter-term, or "shallower" form of assistance -- you aren't going around asking questions to help the police, but are instead answering the questions the police gave. (If you said "I am assisting in the police inquiries," you would be presumed to be doing a share of the work.)

So you can assist your co-worker with a project, or you can assist your co-worker in his work, and it means pretty much the same thing. (Though even there, notice the nuance: a project is a thing with an end, while "his work" is more open-ended!) But you want to be careful saying you're assisting the police in their investigations unless you mean that you're doing more than just answering a few questions.

However, even if you use the "wrong" in/with, a sentence in context will usually be interpreted the correct way.

Answer 2

FROM THE BOOK "Dictionary of American Idioms and Phrasal Verbs"

assist someone in something - to help a particular person working on a task.
Examples: 1. Please assist Greg in the committee’s assignment. 2. We assisted him in the whole procedure.

assist someone with someone or something - to help someone manage someone or something, especially with lifting or physical management.
Examples. 1. Assist me with Jane, won’t you?
2. Will you assist me with this heavy box?
3. Sally assisted herself with the math problem. She did it on her own.