No visual on file
Paradox & Proof
Entry #0156
The reason improving every hospital can worsen the statistics
Every department improved. The overall figure got worse. Both statements are true at once, and the reason is one of the most useful traps in data.
Master
The hidden part
#0156
A total is not a neutral summary of its parts. It is the result of a grouping decision, and that decision can point the conclusion in either direction.