The age for a source to be considered 'too old' depends on the field of study and the type of research you are doing.
Things to consider:
- What does your assignment brief say? If a date range is specified, then stick to it.
- Some fields evolve rapidly. New discoveries or technological changes can quickly make older research out of date.
- Social trends, laws, policies, and behaviours can change over time, but some remain relevant for decades or longer.
- Classic studies, key papers, or theories can be relevant regardless of age, and are often referred to in later works.
- Historical texts, original works of literature, and philosophy are useful in some subject areas, again, regardless of age.
Any work can become outdated if new evidence or methodologies emerge.
In a nutshell:
- Stay current: Prioritize recent publications when dealing with rapidly evolving fields.
- Use older sources that have enduring influence or foundational value.
We recommend the APA advice on outdated sources.
