"Use natural experiments to find hidden causal effects Bapu Jena, a physician-economist at Harvard, pioneered using 'natural experiments' in medicine — moments where circumstances randomly change in ways that let researchers measure cause and effect. He found, for example, that high-risk heart patients actually had lower mortality when senior cardiologists were away at conferences, suggesting that more invasive treatments by senior doctors sometimes do more harm than good. As Jena explains, natural experiments let researchers answer questions that would be unethical or impossible to study deliberately, revealing that 'the most senior cardiologists are more likely to opt for more invasive and riskier treatments.' Anyone trying to understand whether a habit or intervention is actually helping — not just correlating — can look for naturally occurring disruptions in their own data to test causation. Source: Bapu Jena, Freakonomics Radio, Smartphones, Online Music Streaming, and Traffic Fatalities"