Warning: false sense of certainty from the illusion of accuracy and precision in measurements

The illusion of accuracy and precision in testing is often associated with overconfident safety checks before catastrophes: National Aeronautics and Space Administration (NASA) “no safety-of-flight issues,” Deepwater Horizon site in Gulf Mexico reported as “industry model for safety” a year before its explosion, and Fukushima nuclear plant safety test found “satisfactory” at seismic magnitude viewed highest possible. In health care, testing overuse and misuse play significant roles in overconfidence and mistakes. Gaps between systems are most susceptible to errors, such as in miscommunications between the laboratory and the clinic. A safety culture is characterized by ability to communicate, anticipation of misunderstanding and resilient learning from failures. The discussion will show how messages from the laboratory may reduce the false sense of certainty from a test result; how results of tests are meaningless without pre-test estimates; how multiplicity of routine tests increases chances of false positivity; and how reporting measurement limitations can educate all users, including laboratory technicians, clinicians and patients, about the importance of quality assurance and about the pervasive nature of uncertainty beyond analytical performance. In conclusion, an illusion of accuracy and precision in testing evokes among clinicians a false sense of certainty leading to overuse and misuse of tests. Messages from the laboratory may reduce overconfidence from test results and lead to safer use of testing.