English usage question: can "and" and "as well as" be used interchangeably?

I have always believed there is a slight difference in meaning between “and” and "as well as, and I edit accordingly. However, I can’t count the number of times I have come across sentences like this one:

To me, that is wrong – to be correct the sentence should say (forget the question of using an Oxford/serial comma for now – that’s a different subject):

In Nigeria, a market survey was used to gather quantitative and qualitative information about buyers, sellers, volumes, prices, market trends, market share, and market segments, as well as qualitative information on competitors.

I don’t substitute “as well as” for “and” to connect the last two items a series. I use “as well as” only when tacking on an item that is somewhat conceptually different from the ones preceding it:

The proposal was nixed by delegates from the south, west and east, as well as by the President.

What do other Dopers (especially Americans, since that is the standard to which I’m editing) have to say? I want your thoughts, opinions, observations and ideas, as well as any totally irrelevant but amusing comments you care to add.

No idea what the style books might say, but to my eye/ear “as well as” connotes something that is somewhat out of the ordinary in relation to the other items on the list and should not be used in place of “and.” So I would write the series the way you did, not as your quoted sentence would have it.

IANA expert, but I write a lot of material at work (proposals, design docs, etc) & my product is generally well received. I also use “as well as” regularly.

I agree with the OP & Otto; the OP’s coworkers are clueless.

From Theodore Bernstein’s The Careful Writer:

Bernstein was chief copyeditor for the New York Times and was writing in 1965 using real examples from the paper. He was a conservative even then, and usage has loosened considerably since.

Nor does that discussion touch directly on the OP’s issue, but I quoted it for the first and last sentences.

What is the logical force of the OP’s sentence?

They gathered two types of information on everything except competitors. So competitors does need to be set off. However, “as well as” meaning “and not only” is wrong. I would emphasize its exceptionalness by using “but only.” Therefore logically:

Sometimes trying to decide between two alternatives blinds you to the reality that neither of them is right. :slight_smile:

What about using “As well” to start a sentence in place of “And” or “Also”?

Bernstein again:

Your as well should be “In addition,” “Also,” or rewritten.

I loathe “also” as the first word of a sentence. I catch myself doing it every so often and immediately rework it.

But isn’t that what’s happening in the sentence you quoted? The last item is somewhat conceptually different from the ones preceding it–the ones preceding it all have quantitative and qualitative information, whereas the last one only has qualitative information. Or am I reading the sentence differently than I should?

The difference is that I used an “and” to link “south, west and east” and then used “as well as” to serve a different purpose, whereas the sentence I quoted about Nigeria did not use an “and”; it simply substituted “as well as” for “and.”

I appreciate all these comments … what great insights (and confirmation of my own feelings on the matter, which is always welcome :wink: ).

I agree with the OP. Try putting the items in a different order, with a different item following “as well as.” The meaning is not the same. That phrase describes something that is, in some way, different from the others, and you need the “and” before the preceding item.

Try replacing the last comma with a dash, and that accentuates the difference between the last term and the others.