410 likes | 1.05k Views
Dr. Toru Nakata National Institute of Advanced Science and Technology, Japan. Nov. 20, 2011. Human Error — Theory and Prevention . Part I. Theory of Human Error Prevention. 1-1. How we make mistakes . Why do we err?. Unknown Even masters of chess sometime commit easy mistakes.
E N D
Dr. Toru Nakata National Institute of Advanced Science and Technology, Japan. Nov. 20, 2011 Human Error — Theory and Prevention
Part I Theory of Human Error Prevention
1-1 How we make mistakes
Why do we err? • Unknown • Even masters of chess sometime commit easy mistakes. • A lot of typical pattern of “misconception” are found. • Four-card problem • Monty Hall problem • Horse Trading problem • … • But there is no universal tendency among them • Change the question more productive. • “Why can we usually avoid errors?” • Because we can notice and fix errors before they break out.
Horse Trading Problem • Frank sells Sue a horse for $60. • Then he decides he wants it back, but Sue makes him pay $70 for it. • Then Sue changes her mind and buys it back from Frank, but for $80 (Frank is no dummy). • Finally, Frank buys it back from Sue for—you guessed it—$90 (Sue is no dummy, either). • At this point, who comes out ahead? • http://ohiorc.org/for/math/stella/library/problem.aspx?id=128
1-2 Typical Example of Human Error Accidents
Case 1: Confusing patients (1999, Japan) • Patient A: 74 yrs old. Plan to be undergone surgery on his heart. • Patient B: 84 yrs old. Plan to be undergone surgery on his lung. • Loaded an elevator together, • Mistaken each other, when they brought out of the elevator. 7
But, it was doubtful… • Some staffs in the operatin room said, “Is he patient A?” • Different face, vital signs, etc • Reconfirm by telephone to the patient room • “Have Patient A been moved to the operation floor?” • The answer was “yes” • Yoshida Kenko, a famous author, said in his book “Tsure-zure-gusa”, • The top secret skill of horse riding is “do not ride the horse, when you cannot convince the situation is perfect.”
Case 2: Bhopal accident(1984, India) • Safeguards are not safe. • Because, the management for safety becomes reluctant. • Multiple Safeguards seem highly enough. • In actual, all safeguard did not work enough. • Not maintenance for them.
1-3 What is real meaning of Human Error?
Don’t say “error”, use term “uncertainty” • Is “error” wrong? Some errors bring good results at last. We cannot define “error” as a bad. • What you are thinking is “uncertainty” in the work flow.
Part 2 Solutions for Human Error Prevention
2-1 Techniques to ensure human ability
Wake! • 1) Fool-proof • If the driver sleep, the train will stop automatically (Fig.1) • 2) Fool-Trap • If the driver violates speed limit, he will be injured before he hit somebody else. Fig. 1 Train console Fig.2 Bump of the road.
Look your task! • 3) Keep consious about your task. • Sing work songs. • “Cell Production system” • 4) Comfortable weather • People become thoughless when it is too hot or cold. Boring line work Cell Production
Check with objectiveness • 5) Use body and voice together • Pointing and Calling • 6) Check by pair • “Pair programming” in software production. Check with argument Check with reporting number Yes/No check Most easy and unreliable.
This is not end! • Prevent sense of achievement at too early timing Staffs are making a line when their task already finished. They think they have to keep their tension until this ceremony.
2-2 Tool and System to prevent human errors
Zoning Zoning Zoning for sanitary No zoning
Metaphor Remove before flight strap representing the mode of door safeguard Tablet representing right to go forward Starbucks
Pop-out effect Which is reverse? Which is reverse? Is somebody there?
2-3 Planning the strategy
Event Tree Analysis (ETA) Loose file Mistake files Reek files Mistake buttons Mistake Email address Business stops Ordinary problem Other Other • Think risk of severe accidents from ordinary problem.
Think the cause of a particular severe accident by asking why. Fault Tree Analysis (FTA) Iceberg shipwreck Collision with other ships No aids Titanic Lack of Boats No rescue Paticular accident you have to prevent High sea
How to gather incidents reports easily • Easy to write in. • Bring the data into Excel, and sort them. • By sorting, you can find which features (when, where, ….) have got the most reports. • That are the most dangerous features.
Slogan: “Safety by walking around” • Hawthorne effect: • Under the situation that somebody may watch your working scene, you tend to perform better, quicker, and safer. • The watcher is NOT his boss. • Without duty, people naturally try to show themselves as good workers. • Walking around. Meet various staffs who are not bosses nor subordinates in order to encourage them. • Negative Hawthorne effect: • Under the situation that your supervisor is watching you closely, you fell uneasy and tend to refuse the observation. Open Kitchen. The cook tend to perform better and more moderate, because somebody may watch him.