Correlation does not imply causation. It only says the two factors are related somehow - not that change in one affects the others directly. For example, the sales of ice-cream and sales of air conditioners may both go up during the summer season. Hence, they are correlated but one is not the cause of the other. In certain cases, correlation may be because of a causal relationship (eg: poverty and malnutrition) but this is not always the case. It is very important to understand this distinction.