a causal link — cause-and-effect connection (formal/academic)
a relationship where one thing directly causes another, often used to discuss scientific, social, or academic topics where proving cause and effect is important.
Say it like a native
Textbook Researchers proved a relationship of cause and effect between the two.
Native Researchers established a causal link between the two.
In academic writing the fixed term is 'a causal link'; 'a relationship of cause and effect' is a clumsy paraphrase.
Pattern: a causal link between A and B
In use
- Researchers found a causal link between air pollution and increased rates of asthma in children.society
- While many studies have shown a correlation between screen time and poor sleep, few have established a clear causal link.IELTS speaking
Common mistake
✗ There is a casual link between smoking and cancer.
✓ There is a causal link between smoking and cancer.
'Causal' (cause-related) vs 'casual' (relaxed) — one letter, opposite meaning.
Common collocations
establish a causal link between— establish, prove, between ... and, no
Don't confuse it
Unlike 'a connection' or 'a correlation', which only suggest things are related, 'a causal link' means one thing directly causes the other. This is more precise and formal.