Regression to the Mean

Regression effects are a common source of trouble in research, and experienced scientists develop a healthy fear of unwarranted causal interference. We shouldn't be surprised that the very best candidates often fail to meet our expectations. What she doesn't understand is that it's all due to regression to the mean. Perhaps his second interview was less impressive than the first because he was afraid of disappointing us. But more likely, it was his first that was unusually good. So we should anticipate regression.