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Margin of Error

On my way back from Tunisia via Paris I ended up in a redneck dive bar somewhere in Georgia reading the New York Times on my Kindle while the lady next to me asked the very drunk waitress if she knew who had won at NASCAR this weekend.

This sounds like the beginning of a joke, but it isn’t.

Yes, it is your fault, Delta Airlines and U.S. Border Patrol, if you’re listening, which I am sure you are not.

The first concern came when I looked at my ticket and saw that I had an hour and twenty minutes between arriving from Paris and leaving for Los Angeles. This did not go well. The passport control computer had some problem which resulted in hundreds of people being stuck waiting for an hour or more to get their passports checked. By the time we got through, we had all missed our flights and the same hundreds of people were sent to Delta Airlines which very unsympathetically said it was not their fault that people missed their flights because it was the federal computers and we all needed to pay for our own hotel rooms and fly out in the morning.

Why is it that we are eager to invest in mortgages, securities and more, with companies assuring us that they can predict the future well but then other companies, with a lot fewer unknowns, swear that they cannot predict problems and “It is not our fault”.

Being the good statistician I am, I started asking people in line who had missed their flights and were getting re-booked, on the shuttle to the hotel and at the hotel how long was the layover between flights. Every one of those people had a layover between one hour and ninety minutes. No one who had a two hour or longer layover was in the very large group of people who missed their flights.

You know how the airport tells you to show up two hours early for international flights? That’s a good idea. You should do that. I have never missed a flight when I came two hours early, although I have sometimes made the plane by just ten minutes or less.

If Delta had a rule in their computer system that did not allow passengers to have flights closer than two hours together when making an international connection, problems like those that happened today would occur far more rarely. They could even have a manual override on that so if you chose to cut it closer, on your head be it. The extraordinarily UNhelpful customer service person at Delta said to me,

“But it was not our fault. Why should Delta pay for your hotel room? If everything had gone right, if there hadn’ been any computer error, then all of these people would have made their flights.”

That is probably true, however, a system that allows for no margin of error, that assumes “everything will go right” is a bad system and it IS their fault. Of course, if Delta implemented my system, they would sell fewer flights. The problem currently is that people like me assumed Delta personnel knew what they were doing, especially given that Atlanta is their hub, and that if, even though the norm is two hours for international flights, they allowed an hour, they must have some knowledge we didn’t.

In fact, it appears that they were willing to accept the risk that hundreds of passengers would miss flights because hey, it didn’t cost them anything but a little aggravation.

I started out my career decades ago as an industrial engineer. Every industrial engineer knows there are two types of hours, standard hours and actual hours. A standard hour is how long it takes to make a widget. You do a time study and figure that it takes five minutes to weld it, an hour for it to be in the cooling area, and another 15 minutes to sand the edges. So, the part takes an hour and twenty minutes in standard hours. Only a complete moron would base their factory schedule or any other plans on that. You see, sometimes, the machine breaks. You run out of parts. The guy who is supposed to be doing the welding is in the bathroom for 10 minutes or out sick for the day. Often the actual hours it takes to get a part done, allowing for machine downtime, operator sick days, parts shortages, and other problems is about double the standard hours.

What about Passport Control? They were the second group that said,
“Hey, it’s not our fault, it’s the computer.”

That has got to be the biggest bullshit excuse on earth when used by anybody. I don’t mean it was the poor guy at the customs’ booth’s fault, but I definitely think if your computer doesn’t work it IS your organization’s fault. You chose to save money by not having a back-up system, but not having enough IT people on staff, by not paying your programmers well enough that you didn’t have a system in place to anticipate this.

If the problem is that there was a failure in accessing the passport database, you can’t tell me there isn’t a back up of that database made nightly. No one thought of having a system where you can switch to the back up?

I can’t say what the specific problem with the computer in U.S. Customs was, but I am skeptical that the problem was unforeseeable and unsolvable, just based on my own decades of experience with computer systems. I find it more likely that there was a decision made somewhere that weighed the costs of possible failure against the costs of back-ups and alternative systems. Since the costs of, e.g, lost revenue from flights or paying extra programmers would be borne by the company/ agency and the costs of staying overnight, missing flights, etc. are borne by consumers, there is an incentive to short-change on customer service.

Computers aren’t delivered by God and programmed by archangels. Organizations make choices in the programs they use, back-ups they purchase and people they hire. If you cut corners to the extent there is no allowance for error then, yes, it IS your fault.

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  1. Leslie Kish pioneered the concept of “margin of error” in his Survey Sampling book published in 1965. It’s possible that the federal computing systems in use today actually predate that. (It’s amazing to me that a concept that we treat as so fundamental was basically invented just a generation ago.)

    Unfortunately, Kish passed away in Oct 2000 so he cannot weigh in on the debate. He was 90 years old (+/- 3 years).

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