Safety Culture Excellence®

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Probability: Group Experience

April 1st, 2015

A worker using the wrong tool for a job injures his hand.  Another worker has used the same wrong tool numerous times with no injury.  One worker retires having used this tool his whole career with no injury and another retiree has had three injuries related to using that tool.  Each experience is different, and thus, each perception of the risk is different.  Some think the practice is dangerous and some think it is not.  Who is right and who is wrong?

We express a range of experience mathematically by calculating probability.  With enough data points we can establish a pattern to this risk that may not be obvious to anyone who is a data point, but is accurately describing the experience of the large group.  Sharing the findings of a probability study can actually change and norm the perceptions formed by differing experiences within the group.  This new perception can more accurately describe the risk and encourage taking precautions against the risk even among those whose experience hasn’t detected the possibility of accidental injury.  Perceptions, if not thus managed, will vary by experience.  Managing the accuracy of perceptions is a powerful tool for improving safety performance that many organizations have not utilized.



-Terry L. Mathis


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Terry L. Mathis is the founder and CEO of ProAct Safety, an international safety and performance excellence firm. He is known for his dynamic presentations in the fields of behavioral and cultural safety, leadership, and operational performance, and is a regular speaker at ASSE, NSC, and numerous company and industry conferences. EHS Today listed Terry as a Safety Guru in ‘The 50 People Who Most Influenced EHS three consecutive times. He has been a frequent contributor to industry magazines for over 15 years and is the coauthor of STEPS to Safety Culture Excellence (2013, WILEY).


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