Absolute Risk vs Relative Risk

We’ve all encountered claims about drugs boasting incredible results. For instance, imagine a drug that claims to reduce the risk of a heart attack by half. You might think that this means a 2% risk has now become a 1% risk. However, this interpretation is incorrect. In this example, let’s assume the 5-year risk of experiencing a heart attack is 2 in 100 (2%). A group of patients treated with the new drug reported a 1 in 100 or 1% occurrence of heart attacks, making the absolute difference 1%.

To calculate this difference, you might subtract the two risks: 2% – 1%, which equals 1%. However, claims like the one in the example above often uses relative risk, not absolute risk. They take the 1% as 50% of 2%, a 50% reduction. This presentation of the odds can be quite misleading. It’s crucial to understand the difference between absolute and relative risks if you want to know the truth and have all the honest facts.

Let’s break it down using the above example. If we rewrite the claim using absolute risk, it appears less impressive. The pharmaceutical industry often uses mismatched framing to make benefits seem larger and harms smaller. This tactic typically goes unnoticed by those making decisions based on such data. Understanding this concept and recognizing when it’s used is essential.

Take the early days of the COVID-19 pandemic as an example of mismatched framing. When the virus first emerged, scientists released information that the media quickly picked up. Early estimates suggested a 4% chance of contracting COVID-19, a 2% chance of requiring ICU care, and a 2% risk of dying. People interpreted these numbers as a 2% chance of dying from COVID-19, causing widespread panic. However, we now know that the risk of dying from COVID-19 is closer to 0.00024%, which is a significant difference compared to the initially reported 2%.

In this case, an absolute 4% chance of catching COVID-19 was reported, followed by a “relative” 2% chance of those people ending up in the hospital, and finally, a “relative” 2% chance of dying for those in the hospital. This example demonstrates how a percentage of a percentage can lead to misleading conclusions.

As we can see, how risks and percentages are presented can significantly impact people’s perceptions and decisions. This is why it’s crucial to be cautious when interpreting data, especially regarding health-related information. To make informed decisions, it’s essential to understand the difference between absolute and relative risks and to be aware of the potential for mismatched framing.

One way to approach this is to seek clarity on the presented data. When you encounter statistics or percentages, determine whether they are presented as absolute or relative risks. If you’re unsure, ask for clarification or conduct further research to ensure you understand the information clearly.

Moreover, consider seeking information from multiple sources to gain a more comprehensive understanding of the situation. This can help you identify potential biases or misrepresentations in the data, making it easier to make informed decisions.

In conclusion, being vigilant about how data is presented and understanding the differences between absolute and relative risks can help prevent misleading conclusions. By seeking clarity and conducting thorough research, you can ensure that you have accurate and honest information when making important decisions.

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