via U.S. airlines continue on-time improvement in February – USATODAY.com.
Wow. 83% on time arrivals. And by “on time” we don’t mean, well, on time. On time is defined as within 15 minutes of schedule. The article compares the February on time percentage with January and with February of the previous year. This February was better. Of course, the root cause is assumed to be known: what else but the economic downturn?
Notably absent are control charts showing the on time percentage over a significant period of time, any discussion of special versus common cause, or any other indication that the author is aware of the basic concepts of variation. Also unmentioned is the fact that 17% late means that 82,960 flights arrived late in February. If the average flight carried 100 passengers this translates to 8,296,000 passengers who were late. But hey, why complain? The headline makes it clear that we should be celebrating! Since I don’t want to be the wet blanket at this party, I’ll end this posting now.
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