At least two major groups have problems distinguishing between something that causes an event and something that correlates to an event. These groups are a) academic humanists [English Depts., for example] and b) the press. The former enjoy leaping to conclusions, and the latter needs attention-grabbing headlines and leads.
From stats.com, here is a crisp discussion of the difference between cause and correlation:
One of the most common errors we find in the press is the confusion between correlation and causation in scientific and health-related studies. In theory, these are easy to distinguish — an action or occurrence can cause another (such as smoking causes lung cancer), or it can correlate with another (such as smoking is correlated with alcoholism). If one action causes another, then they are most certainly correlated. But just because two things occur together does not mean that one caused the other, even if it seems to make sense.
Unfortunately, our intuition can lead us astray when it comes to distinguishing between causality and correlation. For example, eating breakfast has long been correlated with success in school for elementary school children. It would be easy to conclude that eating breakfast causes students to be better learners. It turns out, however, that those who don’t eat breakfast are also more likely to be absent or tardy — and it is absenteeism that is playing a significant role in their poor performance. When researchers retested the breakfast theory, they found that, independent of other factors, breakfast only helps undernourished children perform better.
*So what caused the oil leak in the Gulf? It’s probably safe to say broken-and-or-failed equipment caused the leak, but it’s also probably prudent to keep in mind many possible correlatives, such as off-shore drilling itself, off-shore drilling in particular areas, the practices of a particular drilling company and its crew, and so on.
*Even in the case of smoking and lung cancer, there are correlatives involved, yes? –Such as genetic factors. But no doubt stats.com and others have plenty of evidence on their side to claim that, indeed, habitually smoking tobacco can and may cause lung cancer.