You may know that I teach and write on Performance Metrics, and get really frustrated when I see someone use them badly. Here’s an example from an article in The Japan Times about the Boeing 787 MAX:
“…the FAA completed a risk analysis that found that the uncorrected risk to the 737 MAX was 2.68 fatalities per 1 million flight hours, which exceeded the FAA’s risk guidelines of 1 fatality per 10 million flight hours.”
Note how they used a different base number for the two ratios ,,, 1 million vs. 10 million. This allowed the numerator to only be 2-3 times the numerator of the guideline, which doesn’t sound all that bad. But if you convert the 2.68/1million to the appropriate 10 million number it would be 26.8, or nearly 27 times guidelines! That’s for sure pretty significantly different!
Wonder of this was done based on ignorance of the writers/editors of how to do comparisons, or if someone was influenced to make it look better?