The writer should be able to attribute any assertion the article makes to someone or some source, so s/he has to do at least that much research, or interviewing. Then s/he has to know the audience — one would do far more research some publications than others. Your tags include “writing” and “journalism”. Are journalism classes still teaching “good journalism is almost never good writing”? If you’re reporting, your job requires just enough research to satisfy the who,what,where,when,how — that’s all. Then s/he has to write clearly, for which one piece of advice is “say it, then quit”.