Sometimes researchers find an association between something that is done, and something that happens.
For example, in some countries ice cream sales and drowning are linked. When more ice-cream is sold, more people drown. That does not mean that eating ice cream causes people to drown. A more likely explanation is that people eat more ice cream when it is hot and they swim more when it is hot. So telling people to stop eating ice cream (an intervention) is very unlikely to reduce the number of people who drown!
REMEMBER: Think about whether you can be sure that there aren’t other reasons for the association.