Not all periodicals are appropriate for research. You must read, analyze, and evaluate which articles to use.

Popular magazines may be easily read, but when a subject is "popularized," important information may have been omitted. A magazine writer, not a professional in a subject field, is more likely to make mistakes in presenting the information.

Scholarly journals may present problems too. Scholars are notorious for using a specialized vocabulary or jargon that may make understanding journal articles difficult. And battles have been waged by rival theorists and academics in the pages of journals, so even there you can't just take one person's word. There is a major controversy in the medical field about the amount of advertising by drug manufacturers in medical journals and what conflicts of interest that may create.

Trade publications allow you to stay abreast of developments in your field of practice. Be sure to distinguish between reporting and advertising.

For research involving a current event or a news-making topic from any time in the past two hundred years, even though they are not "scholarly," newspapers and magazines are a good source. For example, you can follow the presidential campaigns of Abraham Lincoln as they were originally reported in the New York Times.