A courtroom weighs a calm eyewitness against an anonymous rumor differently. Evaluating sources is that same weighing — who wrote it, when, and why decides whether a claim is strong evidence or something you set aside.
Not all sources are equal
Good research rests on credible sources. Evaluate a source by authority (who wrote it, and are they qualified?), accuracy (is it supported by evidence?), currency (is it up to date?), and purpose (is it informing or persuading/selling?). Scholarly sources — peer-reviewed journal articles — carry more weight than anonymous web posts.
Before publication in a scholarly journal, experts in the field scrutinize a paper's methods and claims. It's not a guarantee of truth, but it filters out much weak work.
For a medical claim, a peer-reviewed clinical study outweighs a supplement company's advertisement — different authority and purpose.
- You have a peer-reviewed study and an anonymous blog post making opposite claims.
- Apply the authority and purpose criteria.
- Decide which is the stronger source and why.
What you should see: The peer-reviewed study wins on authority (vetted experts) and purpose (to inform), making it the stronger evidence.