Methods of causal inference are not widely used by education researchers, even though they can be extremely useful tools for eliminating selection bias and confounding factors in empirical studies. For example, researchers have established that taking additional math classes in high school is strongly correlated with success in college and higher earnings. More recent research seeks to show that taking additional math in high school actually causes success in college. Such analyses are difficult because researchers must draw meaning from naturally occurring data, rather than through experimentation. Researchers have employed a few different methods of causal inference with varying levels of success. Studies using the best methods suggest that taking additional courses in high school mathematics does, in fact, cause an increase in college enrollment and future wages. Education researchers should recognize the power of causal inference methods more widely in evaluating treatment effects.