which or that?

[Sioned11]

Section 2 gives additional explanation for error patterns which eluded the retrieval systems.
Section 2 gives additional explanation for error patterns that eluded the retrieval systems.

Sorry, folk - one other question.

My understanding is that if the relative clause is defining, i.e. uses commas, then which is used.
If it is non-defining ie doesn't use commas, then which or that can be used.

And perhaps provides instead of gives. Sounds a bit more formal?

That and which often confuse me ...

Many thanks

Some people (particularly in US, I believe) adhere to a rule that "which" and "that" should be used differently (for restrictive v non-restrictive clauses), but it's a bit of a myth - here's a professional linguist on the subject: languagelog.ldc.upenn.edu/nll/?p=4384

So I think it boils down to how clear it is to your readers. If section 2 only covers elusive error patterns, then is it clearer to say:
"S2 gives additional explanation for those error patterns that have eluded the retrieval systems".

"Provides" is a bit more formal (stuffy?) but do you need to be more formal? Nothing wrong with "gives".

Thank you so much. A very interesting and helpful reply and a fascinating article. I like this linguist's approach, I must say.