Research 101: Hierarchy of sources

Encyclopedias, handbooks =  large volume sets of commonly accepted ideas

Reviewed books = works of more than 75,000 words which have been reviewed by a variety of sources for their research strengths and weaknesses

Randomized trials = tests that evaluate one idea only, not allowing bias or influence from other ideas, from a truly random sample

Peer-reviewed research articles = works of 10,000 - 50,000 words which have been reviewed by a variety of sources for their research strengths and weaknesses

Cohort studies = tests that evaluate ideas, from a sample greater than 10

Case studies = < 10 examples, which may contain unique situational developments not seen in a larger population

Magazine or newspaper articles = works of 10,000 - 50,000 words which have not been reviewed by a variety of sources for their research strengths and weaknesses

Interviews = described discussion with a person or people, speaking not under oath for penalty of perjury

No or little reviewed books = books that were not reviewed by a variety of sources  for their research strengths and weaknesses

Student papers = works written for curriculum submission, including dissertations and theses

Conversations = casual discussion that may allow bias or influence from other ideas

Editorials = works intended to persuade for or against any opinion

Opinions = works that describe only one viewpoint, allowing bias or influence from other ideas

Speeches = persuasive spoken or written rhetoric which is often editorial or opinionated