Double modifiers

[nash.avi]

This is a homemade question:

The professors often criticize college's performance gauged by an index, such as satisfaction test scores, that are/is not dependable.


Does "that" refer to index (then is should be used) or does it refer to test scores (then are should be used)

I'm confused. Could you please clarify and throw some light on this.

Thanks in advance.

cheers

[chintanjpatel]

that is for the index, is should be used. the clause such as after the comma is a descriptive clause. u can omit it. tht will give u a clear idea.

[StaceyKoprince]

chintan is right - "such as" is simply giving an example of whatever it is you're talking about (in this case, the index). The description is necessary, so that people have an idea of what the sentence means when it says "index" - and the "that" clause following just "skips over" the stuff set off by the commas.