Locard’s Exchange Principle at the Gemba:

Harish's Notebook - My notes... Lean, Cybernetics, Quality & Data Science.

In today’s post, I am looking at Locard’s Exchange Principle, named after the famous French Criminologist, Edmond Locard. Succinctly put, the exchange principle can be stated as “every contact leaves a trace.” This is perhaps well explained by Paul L. Kirk in his 1953 book, Crime Investigation: Physical Evidence and the Police Laboratory:

Wherever he steps, whatever he touches, whatever he leaves, even unconsciously, will serve as a silent witness against him. Not only his fingerprints or his footprints, but his hair, the fibers from his clothes, the glass he breaks, the tool mark he leaves, the paint he scratches, the blood or semen he deposits or collects. All of these and more bear mute witness against him. This is evidence that does not forget. It is not confused by the excitement of the moment. It is not absent because human witnesses are. It is factual evidence. Physical evidence…

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