Which vs. What

[Jonathon]

What vendors were on your short list?
What vendor did you select?
What solution or service did you select?
What one person was the most involved or influential in approving the expenditure?
What features of IBM's solution did you value the most and why?


I think these should all be which, but my boss thinks only the second one should be. I can't cite any official rules other than the dictionary definitions, which apparently leave room for debate.

[Brinestone]

I think, in general, what is an open-ended pronoun, whereas which is a modifier and a narrower. You say "which color is your favorite?" but "what is your favorite color?" Does the dictionary say anything about using what as a modifier?

[Brinestone]

Hm. Just checked. I think all of those fit definition 1 for which as an adjective and don't fit any definitions for what exactly. Definition 1 is close, but there is definitely a difference in intention--it's not "which out of a group."  

[Jonathon]

What
used as an interrogative expressing inquiry about the identity, nature, or value of an object or matter

Which
being what one or ones out of a group -- used as an interrogative

It seems that all those questions ask for the respondent to choose something out of a group, even if the group isn't stated.

[Brinestone]

They all mention a group: vendors in the first and second, solutions and services in the third, people in the fourth, and features in the last.

[Icarus]

I agree with Brinestone's first post. "Which" suggests to me a multiple choice. Based on this, however, I tend to side with your boss on this one, at least on three through five. I think they sound better as "what." The "choices" seem too vague and not specifically enumerated to me.  

[Icarus]

I asked my wife, and it seems we all interpret "which" and "what" the same way. I guess it comes down to whether we feel the question is intended to be open-ended or not. With more context we might possibly reach a consensus; then again, it might come down to individual readings or interpretations.

In short, the answer is "whatever."

:-p

[Jonathon]

Actually, that's the conclusion I've come to, too. For example, there really isn't a set list of features that they're choosing from. The answer may very well be something like "The CEO liked it." She still wanted "what" on the first one, though. It seemed like it could go either way, so I didn't argue it.

[Icarus]

Yeah, the first one more than any other seems to me able to go either way.

[pattyshmack]

"What" seems to sound better to me, it leaves some vagueness while, "which" is more specific and narrow.  That's just me.

[kojabu]

What sounds better for the fourth one.