Which construction is correct: “Determine if the process is in control” or “Determine whether the process is in control.” Or are both correct?
Ancillary question: Does use of “whether” also require use of “or”, as in “Determine whether the process is in control or it is varying beyond limits.”
Where can one find these kinds of rules?
IANAGrammarian, but I believe whether requires exactly two alternatives. So “Determine whether or not the process is in control” may be better than “Determine whether the process is in control”.
On the other hand, “Determine whether the process is in control” does have an obvious implied second alternative.
Here’s what my dictionary of choice (WordWeb) has to say about whether:
“whether or not” will make most serious grammarians cringe. Since “whether,” as you point out, indicates two alternatives, the “or not” is egregiously redundant.
“Determine whther the process is under control.”
No “…or not…”;
No “…if…”;
No “…in control…” (unless the process is, in fact, controlling something).
You can get questions about grammar answered with less noise at books.grammarlady.com – it’s a hangout for some fairly serious grammarians, editors, and the like (and a few descriptivists, but they’re easy to spot).
Whether, dammit.
Is it more acceptable if the or not is moved to the end? As in
“Determine whether the process is under control or not.”
Personally, I’ve heard the whether or not construction so many times in formal and informal settings that I assumed it was OK. Maybe it’s idiomatic…
One pointless nitpick: “Determine whether the process is under control.” probably shouldn’t have the capital D and a full stop because it’s not a complete sentence - unless it’s an imperative command.
“Hey! You over there! Yeah, I’m talking to you! Determine whether the process is under control! NOW!”
Regardless of placement, the “or not” is redundant. “Whether” includes the “or not”, just like “descending down the stairs,” where descending includes “down.”
Yes, it’s commonly used, and yes, it’s grammatically repetitive.
I’d like to add that the only time “or not” is correct is when either of two situations applies: “We’re going on the picnic whether it rains or not.” “Whether the allegations are true or not, they have seriously injured the senator’s reputation.” And so on.