Lies, Damned Lies, and Statistics (24): Mistakes in the Direction of Causation

Suppose you find a correlation between two phenomena. And you’re tempted to conclude that there’s a causal relation as well. The problem is that this causal relation – if it exists at all – can go either way. It’s a common mistake – or a case of fraud, as it happens – to choose one direction of causation and forget that the real causal link can go the other way, or both ways at the same time.

An example. We often think that people who play violent video games are more likely to show violent behavior because they are incited by the games to copy the violence in real life. But can it not be that people who are more prone to violence are more fond of violent video games? We choose a direction of causation that fits with our pre-existing beliefs.

Another widely shared belief is that uninformed and uneducated voters will destroy democracy, or at least diminish its value (see here and here). No one seems to ask the question whether it’s not a diminished form of democracy that renders citizens apathetic and uninformed. Maybe a full or deep democracy can encourage citizens to participate and become more knowledgeable through participation.

A classic example is the correlation between education levels and GDP. Do countries with higher education levels experience more economic growth because of the education levels of their citizens? Or is it that richer countries can afford to spend more on education and hence have better educated citizens? Probably both.

Advertisements

3 thoughts on “Lies, Damned Lies, and Statistics (24): Mistakes in the Direction of Causation

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s