Tag Archives: Education Writers Association

Correlation is Not Causation and Other Boring but Important Cautions for Interpreting Education Research

Journalists, as a general rule, use accessible language. Researchers, as a general rule, do not. So journalists who write about academic research and scholarship, like the reporters at Chalkbeat who cover school spending studies, can help disseminate research to education leaders since they write more plainly.

But the danger is that it’s easy for research to get lost in translation. Researchers may use language that appears to imply some practice or policy causes an outcome. Journalists can be misled when terms like “effect size” are used to describe the strength of the association even though they are not always causal effects.

To help journalists make sense of research findings, the Education Writers Association recently put together several excellent resources for journalists exploring education research, including 12 questions to ask about studies. For journalists (as well as practitioners) reading studies that imply that some program or policy causes the outcomes described, I would add one important consideration (a variation on question 3 from this post): if a study compares two groups, how were people assigned to the groups? This question gets at the heart of what makes it possible to say whether a program or policy caused the outcomes examined, as opposed to simply being correlated with those outcomes.

Randomly assigning people creates a strong research design for examining whether a policy or program causes certain outcomes. Random assignment minimizes pre-existing differences among the groups, so that differences in the outcomes can be attributed to the treatment (program or policy) instead of different characteristics of the people in the groups. In the image below, random assignment results in having similar-looking treatment and control groups. Continue reading