Thanks, I have to look up Wigmore charts!

I was intending on having something like confounding bias appear in the form of the protagonist's model of the world being gradually updated to contain larger and more detailed networks, so e.g. two variables that appeared to have a causal relationship in an early network would turn out to have a common cause in a later, more accurate one. (The player can acquire more accurate networks either by allocating time to studies and learning from the work of others, or by experimenting themselves. Not sure of the exact mechanics for these yet.)