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  • 1.  Risk is both severity and probability - but which one matters more?

    Posted 15-Apr-2024 10:38
    Edited by Naveen Agarwal 15-Apr-2024 10:38

    👋Dear colleagues, hello!

    📊Recently I posted a poll question on LinkedIn that generated a lot of good discussion.

    🌟To estimate risk, we need to estimate severity and probability of harm.

    🤔We want to be as accurate as possible in our estimates.

    🔥Often, we don't have a lot of data and we have to make many assumptions. We may overestimate or underestimate risk.

    ❓So which of the following errors in your opinion is more consequential?
    1. Overestimating Severity
    2. Overestimating Probability
    3. Underestimating Severity
    4. Underestimating Probability

    🙏 Please share your opinion and clarify in comments for further discussion. Thank you.



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    Naveen Agarwal, Ph.D.
    Problem Solver | Knowledge Sharer.
    Let's Talk Risk!
    @https://naveenagarwalphd.substack.com/
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  • 2.  RE: Risk is both severity and probability - but which one matters more?

    Posted 16-Apr-2024 02:33

    I have been around for a while, and this is an on-going problem.  I still see companies that say they follow a worst-case scenario with risk management.  When you ask them what they mean, they will tell you that is it based on worst-case severity.  When I then explain to them that they can have a higher risk because of a lower severity, but with a higher occurrence, you can see the light bulb go off.

    Risk is a calculation and both factors in the equation bring something different to give you a better indicator of risk.  I do think the problem is the excuse of "we don't have a lot of data."  The data is out there, and companies have it, but they don't want to mine the data.  I am not talking about complaints.  Complaints are just a single piece of data.  I am talking about the clinical data that most companies already have on their own devices and the competitive devices.  The devices that I work on, the FDA publishes a lot of the data.  Yes, back in the old days we did a lot of guessing, because we didn't have the data, but that has changed.  

    I worked on a device in a past life that had death as a severity all over the hazard analysis.  I asked them why and they explained that all of these things could lead to death.  When I ran a Maude report for our device and the competitive devices, we could find any data to back up their assumptions.

    The other piece of this that I see frequently is that the individuals working on the risk documents do not have a good understanding of the clinical use of the products.  It is important to have a clinician remove the documents, but to also get the people trained on the clinical use of the products.  The doctors love to teach.  I had a doctor spend two days dedicated to working on a hazard analysis with my QE's and engineers.  When they returned, they said that the education they received was better than four years in college.

    This was a long-winded response, but the severity and probability of occurrence are both important numbers and bring separate factors into the equation.  Start with what you know and build upon it during your periodic reviews of your risk files.



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    Christopher Slimak
    Director, Design Assurance
    Stryker - ENTERPRISE
    Warsaw IN
    United States
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  • 3.  RE: Risk is both severity and probability - but which one matters more?

    Posted 16-Apr-2024 08:48

    Hi Chris - thanks for your thoughtful and detailed response. I think you have accurately identified many of the common challenges in the industry. When it comes to the real world practice of risk management, we still have a long way to go!

    I hope conversations like these offer new insights to help practitioners build a more practical knowledge. 

    Thanks!



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    Naveen Agarwal, Ph.D.
    Problem Solver | Knowledge Sharer.
    Let's Talk Risk!
    @https://naveenagarwalphd.substack.com/
    ------------------------------