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Evidence should be put in context, or qualified in Wikipedia articles, especially for sources that should not be taken at face value. Some articles are tagged with {{qualify evidence}}, and this page helps describe what to do for them, and how to treat factual claims in general.
Things to check for scientific studies mentioned in articles:
- Have other studies attempting to replicate the results succeeded, contradicted, or been inconclusive? If no replication has been attempted, that is important to mention in the article because it means the results are significantly less trustworthy.
- What do secondary sources say about the claims? Is there scientific consensus? Are there multiple lines of evidence all pointing in the same direction? Are there competing theories or other possible explanations not mentioned by the study? Are these tested or untested? Are the findings generally disputed or dismissed? Sometimes primary sources contradict each other; see Wikipedia:Identifying and using primary sources.
- Correlation does not imply causation; articles should be careful not to imply results reporting a correlation have found the cause of a disease or other phenomenon.
- Be especially careful with medical studies (more specific advice below).
In general:
- Don't report scientific claims as facts unless there's a scientific consensus supported by secondary sources; otherwise, they need to be attributed to specific studies.
- Predictions about future events (such as economic trends) – even those grounded in studies – are generally not encyclopedic, but some topics about the future (such as global warming and the ultimate fate of the universe) are appropriate, when sourcing is comprehensive and balanced. See WP:CRYSTAL for details.
- Expert opinions unsupported by rigorous study should be avoided, or heavily qualified.
- Watch out for sources representing only one perspective on a controversial question.
Editors may need to:
- Add details from the cited sources that clearly and precisely help readers understand the limitations of the source material.
- Add material from other sources that give context or which are more up to date.
- Caution readers that studies that do not have scientific consensus might not be reliable. For example, link to levels of evidence, explain the strengths and weaknesses of a certain type of evidence, or quantify how likely something is to pan out (e.g. how many drug candidates become approved drugs, or how many psychology studies fail attempted replication).
- Remove sources that turn out to be unreliable.
- Become familiar with the scholarly methods of the specific field.