Check your outlier – is it a symptom or an anomaly?

The shocking United Airlines ejection of a passenger was an outlier

This week I’d like to talk about outliers. These are people, events, or data points that are so far from the norm that they attract unusual amounts of attention. Outliers make the news. Most of the news stories you read concern exceptions or unexpected events. They grab out attention. The disturbing United Airlines’ scene of a paying passenger being forcibly and violently ejected from the plane represents just such an outlier.

Last week, a passenger was brutally dragged off a United Airlines flight in Chicago by security guards who broke his teeth and nose, leaving him with blood streaming down his face and a concussion. He had refused to give up a seat he had paid for, and United decided that he and three other passengers (chosen randomly according to some algorithm) had to leave the plane. The airline had offered travel vouchers (of $800) but no one had taken them, apparently. So it decided – time to draw straws. And what for? So space could be made for four airline employees, arriving at the last minute for the flight bound for Louisville, Kentucky.

The scene of security personnel pulling the 69-year old Asian American (he was born in Vietnam) through the aisle to the horrified looks and gasps of other passengers was filmed on smartphones and duly posted to the web. It has generated a huge outcry and calls for a boycott of United. The company made things worse when CEO Oscar Munoz issued a terse non-apology, blaming the passenger, Dr. Dao, for being “disruptive” and “belligerent”. Munoz wrote: “I apologize for having to re-accommodate these customers,” which is about as far away from saying sorry as it gets before entering antonym territory.

Meanwhile, there are plenty of news articles predicting that the public will get over it, and United Airlines will weather the storm. This is because many companies have overcome this type of scandal in the past, and because many customers don’t have a lot of choice when it comes to airlines. Consolidation among the big legacy airlines, blessed by the regulators, has ensured that.

The shocking incident is highly unusual, which is why it generated so much attention. We are used to hearing about passengers being escorted from flights for misbehaving, but in this case it was the airline which misbehaved (even if it did outsource the job to airport security).

Outliers – good for the news, but not so good for research?

In the research world, outliers are not a news opportunity. Most of the time, they’re viewed as a problem, sticking out like a sore thumb. Outliers raise questions about data reliability and validity. They distort the mean, leaving an inaccurate impression, even if the data is 100% correct. (Remember the one about how Bill Gates walks into a bar and suddenly everyone is a billionaire, on average?) The solution? Outliers are typically ignored or dropped from datasets by researchers.

But outliers can mean different things. They can be symptomatic or anomalous. Maybe an outlier highlights a larger problem, represents the tip of the iceberg, a leading indicator, a canary in the coal mine, i.e. a symptom of some larger phenomenon or a trend that is about to break. Or maybe it represents an exception to the rule, a bad apple, and can justifiably be disregarded. It is also possible that the outlier is an error. Before deciding how to deal with them or react to them, we need to understand what they mean.  If they’re signaling something, then even researchers need to take a closer look at them. Like a doctor, you should check your outlier in order to make a diagnosis.

In a 2002 article, Vijayendra Rao advocates “having tea with an outlier,” i.e. looking more closely at what they represent, and maybe even talking to them if they represent a survey respondent, to get a different perspective on the issues.

The outlier may have different intrinsic characteristics that sets it apart. I was once asked to find a poor person in a village in Kazakhstan in a region where I was conducting an evaluation for the Asian Development Bank. It wasn’t easy, because the people we talked to didn’t really consider themselves poor and had to scratch their heads when we asked them to point us toward a poor household. Finally, my team members and I were directed to the home of a single mother. We brought her some groceries, and knocked on her door. She invited us in and we sat down and talked to her. It turned out that she had emigrated from Ukraine (I can’t remember whether her husband had died or merely left her) and thus lacked a social support network.  She had problems with her papers. There were also health issues. I don’t believe we actually had tea. She was an anomaly, an exception. She didn’t represent the typical inhabitants of the region. While we learned about what kind of factors might drive people into poverty, her case didn’t tell us much about poverty issues among the population as a whole.

The case for symptomatic

But if the outlier represents an extreme case of a phenomenon that is happening to a lesser degree elsewhere, then it takes on a different meaning. What do we have with United? I would argue that the case is symptomatic and not anomalous. Indeed, although it was well outside the norm (the chances of a passenger getting bumped from a flight remain 1 in 10,000, and the chance of losing your teeth in the process remain vanishingly small) the mood against United has been building for some time and helps explain the outrage. United certainly did not have a good customer service reputation prior, and the extreme mistreatment represents, in many people’s eyes, all that is wrong with the company. The frustration and anger over poor service boiled over. United’s reputation was already solidly second rate. It ranks 66 out of 100 global airlines according to one survey.

My own experience flying United is far from pleasant, and presumably widely shared. Anyone who has flown with a European, Gulf region or Asian airline will know that US carriers in general deliver poor service. While with the better international carriers you might feel as though you were their guest, on most American carriers you feel like a revenue source that, inconveniently, must be processed, takes up physical space, and requires (minimal) attention. They get away with it because of a lack of competition, and because they know passengers put up with it because of the relatively low prices.

The irony is that Americans on the whole don’t tend to be unfriendly; quite the opposite. But once hired by an airline, I can only assume that they are processed through some kind of training module which strips away as much of their humanity as possible (although you will occasionally interact with a friendly crew member or ground staff whom the system clearly failed to process).

Finally, CEO Munoz’s initial reaction to back his staff and essentially blame the passenger was very telling and fairly indicative of United Airlines’ attitudes in general. Based on his initial reaction for Munoz the incident was not such a big deal. In other words, it was within the bounds of normalcy. That suggests it was symptomatic, not anomalous. Granted, Munoz did issue a proper apology days later, but that was tainted by the strong suspicion that it was a reaction to the airline’s share price dropping a bit and not some sort of  recognition that it’s approach to customers in general is woefully lacking in common decency.

So while the news articles which argue that United will survive this debacle may be correct, it doesn’t mean that this particular extreme behavior doesn’t mean anything. I believe the evidence supports the view that it reveals a lot. It is symptomatic of a much larger problem – in a word, disrespect toward passengers, those important but still annoying revenue streams.

(If you’re curious, I will do my best to avoid giving United my business in the future, even if it costs extra.)

Inadvertent airline humor

I leave you with some one liners. They are taken verbatim from a link on United Airlines’ own website called, without a trace of irony, Shared Purpose and Values:

• We Fly Right: On the ground and in the air, we hold ourselves to the highest standards in safety and reliability. We earn trust by doing things the right way and delivering on our commitments every day.
• We Fly Friendly: Warm and welcoming is who we are.
• We Fly Together: As a united United, we respect every voice, communicate openly and honestly, make decisions with facts and empathy, and celebrate our journey together.
• We Fly Above & Beyond: With an ambition to win, a commitment to excellence, and a passion for staying a step ahead, we are unmatched in our drive to be the best.

Even setting aside the passenger ejection incident, anyone who has ever flown on United – an airline with some of the most unhelpful and unfriendly employees in the world – will be forced to acknowledge that they do have a dry sense of humor.