Learn English – Correct usage of “persons” (vs. “people”)

The dreaded Elements of Style have this to say on this matter:

The word people is not to be used with words of number, in place of persons. If of "six people" five went away, how many "people" would be left?

So at least in formal or technical discourse you might want to prefer "persons".

I have also observed that "persons" is generally and widely used in official documents, highway signs, etc. in Britain, Canada, and the U.S.

In informal contexts, however, "people" is probably preferable, especially as it will allow you to steer clear of the, er, people from all walks of life who will try to tell you that "persons" is not a valid word at all.

But as both your question and Strunk point out, you should avoid mixing them too much, because there is no exact correspondence between "person"/"persons" and "people"/"peoples".

I too have seen some conflicting articles on this. In general, I use it as follows:

If I'm using people as the plural of person, then I treat it as plural.

These people are going to be the death of me.

If people is referring to a community, cultural group, etc. then I treat it as singular.

This indigenous people was subjugated by invaders from afar.

I'll also note that used in this last sense, peoples (meaning multiple cultural groups, or what have yoU) is also valid and would then be plural.

These indigenous peoples were all prospering at the turn of the century.