Data Quality with Southwest

Data Quality with Southwest

On a recent Southwest flight I was reminded how easy it is for important business processes to fail. The flight attendant came on the speakerphone and politely asked if Eve Adamson (pseudonym) was aboard the aircraft, and if so could ring the attendant call button. If you fly much you know this is a very common occurrence. But if you think about it, this breaks all the rules of common sense and the TSA boarding procedures.

Every passenger must show proper ID when passing through TSA security and again present their boarding pass at the gate in order to board the plane. So if the Southwest (though it could be any other airline) computer registered my QR code on my boarding pass at the gate, how is it that they don’t know if I’m on the plane? Well, a lead steward, with United Airlines, recently explained that sometimes the scanner at the gate doesn’t read the QR code or otherwise log it. I find that very hard to believe, given that every gate attendant I’ve seen, assists you, and glances at the screen to make sure the system accepted my code and that I’m on the right flight. If it didn’t read it or approve me, the gate attendant shouldn’t let me board. So in short, every time you hear them ask if "Eve Adamson" is on your flight, ask them what they mean, because effectively they’re asking if their coworker at the gate correctly boarded each passenger- which I’m sure the TSA cares about.

This is a great example of a business process impacted by poor data quality. Let's assume, for a minute, that their passenger list is indeed deficient (missing a row for Eve Adamson because, but somehow she got past the gatekeeper and is on the plane. If that was the case there needs to be additional controls to ensure that nobody can get on unless they've been checked (maybe the steward at the door of the plain check your name before you board the plane).

After boarding the plane, and getting situated in my seat, another flight attendant went through the normal routine, and mentioned that drink coupons with “valid expiration dates” would be accepted when drinks are served. Having just hosted the IQ International Healthcare DQ Metrics working group session, hours before, where we thoroughly discussed “Validity” and its proper usage, I perked up when I heard her statement. What we say is very important, because our words should express what we mean. Regarding the drink coupons, each coupon has a period of time for which it is Valid. This means that you can only exchange it on or after the beginning date and until the expiration date, but not after the expiration date. These expiration dates are properties of the coupon, and although the steward said that only coupons with “valid expiration dates” would be accepted, she technically meant that only Valid coupons will be accepted (based on the expiration dates). The coupon is the subject not the expiration date. An “Invalid Expiration Date” would be one that is outside of a specified range (1), doesn’t conform to a specific format/data type(2/3), outside of a domain of predefined values(4), or otherwise doesn’t conform to a business rule(5). Using the Conformed Dimensions (below) you can improve customer services, and ensure that what you mean is understood.

DimensionUnderlying ConceptDefinition of the Underlying Concept (CDDQ r4.3)



1.      Values in Specified RangeValues must be between some lower number and some higher number.
2.      Values Conform to FormatValidity measures whether the data are arranged or composed in a predefined way.
3.      Values Conform to Data TypeValidity measures whether values have a specific characteristic (e.g. Integer, Character, Boolean). Data types restrict what values can exist, the operations that can be use on it, and the way that the data is stored.
4.      Domain of Predefined ValuesThis is a set of permitted values.
5.      Values Conform to Business RuleValidity measures whether values adhere to some declarative formula.

So next time you receive a coupon, inspect the expiration dates to see if they are Valid (e.g. doesn’t say something like “before time” or 1000 BC…etc. I’m guessing that every single one of the passengers on the plane had a coupon with a valid expiration date, but that doesn’t mean they are entitled to a drink, because their coupons may be invalid because the current date is outside of the eligible period- most likely after the expiration date.

If you'd like to learn how to measure data quality using the Conformed Dimensions of Data Quality consider the onsite DQ Jumpstart that Dan Myers is teaching on May 17th in Vancouver, Canada. Or consider bringing him to your company to speak <dan[at]DQMatters(dot)com>.