Post hoc ergo propter hoc
Latin for "after this, therefore because of this." A logical fallacy in which correlation between two or more variables is mistakenly interpreted as a causal relationship: B followed A, therefore A caused B. In manufacturing terms, operator A produced parts for four hours without producing any defectives, but operator B took over and x number of defectives were produced. The fact that there is a correlation between operator B’s arrival and the production of defectives doesn’t necessarily mean that operator B was the cause of the problems—there might have been other factors at work, such as material, tool wear, machine maintenance, etc.
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