Friday, August 3, 2007

Mixing Alphas and Oranges

This is my first post having to do with design. By design I mean very generally the way an artifact of any sort is thought about before it is built. It could be anything - an apartment building, a tourist map, a toaster oven, a website, a cellphone or, in this case, the set of announcements used on the subway system at the Atlanta airport.

You may have thought that the nerds responsible for creating computer programs had a monopoly on bad user interface design, but think again. A ride on the subway at Atlanta airport demonstrates convincingly that geeky thinking abounds, and that it is not restricted to hard-to-use PC applications.

"Wait a minute," you may object, "there's no user interface on the Atlanta airport subway." There is one, but it doesn't involve a mouse, or a keyboard, or an LCD monitor. The one I have in mind consists of the spoken messages that are broadcast as the train approaches and leaves each station. Their construction is a wonderful example of how technical knowledge in the wrong hands can be a confusing, if not a dangerous, thing.

To give you a sense of where I'm going with this, complete the following sentence,

A is for ...

If you responded with "apple", then, like the vast majority of English speakers, it is an association so natural, it seems reflexive. Then again, if you responded with "alpha", there may be a job waiting for you with the same outfit that scripted the airport subway announcements. For those guys concourses A, B, C, D, E, and the oddly named T, are best identified as alpha, bravo, charlie, david, echo, and tango, respectively. Why is this and why is it a bad idea?

The origin of this instance of interface design obtuseness is rooted in an inappropriate affinity for technology - or in this case, technologese. The alpha-bravo-charlie, triad is familiar to some of us. We hear it often these days in battle reports from Iraq which may refer to an alpha battalion or a bravo company, for example. The use of these alphabetic placeholders in the military derives from - and is best illustrated by - the "aviation alphabet" which defines word correspondences for each English letter. Apparently someone working on the announcement system had the bright idea that, since there was a need to identify letter-designated concourses and these concourse were, after all, part of an airport, then the ready-made aviation alphabet was a good fit. Indeed, it had been around for for decades. Why reinvent the wheel?

Well, the fact of the matter is that the aviation alphabet came into being to meet a specialized need, and that was the need to transmit letters clearly and unambiguously over what were often noisy and only intermittently reliable radio channels. Associating letters of the alphabet with words made it more likely that they would be heard over the crackles and pops of radio static. Choosing these words carefully made it less likely that one letter would be confused with one another. The advantages of these so-called "phonetic" alphabets should come as no surprise, since each of us, every now and then, has to struggle transcribing a confirmation code - usually a mix of numbers and letters - as it is spoken to us over the phone by a hotel reservation agent, for example. To do this we often resort to our own improvised phonetic alphabets, typically consisting of commonly occurring first names or other simple words.

So aviation alphabets come in handy when there is a need to transmit arbitrary letters reliably, either individually or as part of a mixed sequence of letters and numbers, over a noisy communication channel. Not exactly the requirements that emerge when facing the challenge of announcing the single-letter airline concourses encountered - always in a predetermined order - on the Atlanta airport subway. But there is another feature of aviation alphabets that makes their application to the airport subway especially misguided. That is that, in order to be at all effective, the people who employ these letter substitutions - both those speaking and those spoken to - are presumed to have studied them well in advance. In fact international standards have evolved to define the exact letter-word correspondences and to detail their precise pronunciation so that users can become proficient.

Now the likelihood that a given passenger riding the airport subway in Atlanta is familiar with the aviation alphabet in its full-blown glory is slight, but that hardly matters since mapping alpha to A and bravo to B and the like is hardly a challenge for an experienced English speaker. The problem is, of course, that we are talking about Atlanta Airport - a.k.a. Hartsfield-Jackson International Airport - and, consequently, many of the 80 million of so passengers who ride the airport subway every year are not only not native English speakers, they may in fact have only a cursory knowledge of the English language. Of course, if they know no English at all, there is little the aviation alphabet or any other could do to assist them. But, to the extent that they know a little English, the following alternative associations would probably sound much more familiar to them

A as in Apple,
B as in Baby,
C as in Cat,
D as in Dog,
E as in Elephant,
and T as in Television

(These are my own untested suggestions. I will leave it to the reader to provide his or her preferred substitutions.)

Now the point of this discussion is not to revise the script of the Atlanta airport subway announcements, although I would be pleased to see that happen, but to provide an example of how clumsy design ideas arise and how they can be avoided. To bring the matter home, consider the story of the letter D in the original version of the airport subway script.

Two years ago, as I recall, shortly after the aviation alphabet system was put in place, a subway rider outbound from airport concourse C would have heard the following announcement coming from the loudspeaker, "the next stop is concourse D ... D as in delta." The selection of this particular substitution, delta for D, in complete conformance with the NATO phonetic alphabet I might add, was no doubt a disaster. As anyone familiar with Atlanta airport knows, it is a hub for Delta Airlines, which uses, I would guess, about half of the gates there scattered among almost all of the concourses. An unfortunate traveler, unaware of Delta's dominance in the Atlanta market and desperately trying to make his or her way to a connecting Delta flight, would hear the magic word "delta" as the subway pulled into concourse D and would exit the train to march down the corridor only to arrive at what would likely turn out to be an incorrect departure gate. I'm not sure how long it took the airport authorities to notice this problem and replace "delta" with "david" in the concourse D airport subway script, but I suspect it required numerous complaints from angry misdirected airline passengers.

The misapplication of the aviation alphabet to this situation and the truly ill-advised use of the word "delta" to designate a concourse at Atlanta airport illustrate a not uncommon design failure: that is a failure of imagination. By imagination in this context I don't mean the kind of visionary genius that is the engine of true innovation. I mean more prosaically the activity of imagining how a product - in this case a subway announcement system - will be used in practice. This kind of imagination requires that the designer or designers place themselves in the position of the variety prospective users of their creation and mentally step through numerous scenarios that these users may encounter.

This was the kind of imagination missing from the process that led to the selection of the aviation alphabet for concourse identification in the airport subway. My guess is that the people who formulated the scripts didn't think much about them, certainly not about the context in which they would be used, specifically the number of non-proficient English speakers who would rely on them for assistance. There was a readily available technical "solution", the aviation alphabet, which seemed superficially appropriate - after all, it was the aviation alphabet - in addition, it had the imprimatur of an international standards organization which made it an easy sell bureaucratically.

Now I'll be the first to admit that the use of the aviation alphabet as part of the scripts for the Atlanta airport subway is hardly a design catastrophe of the first - or second - order. But, as an example, it does capture quite compactly how apparently "safe" engineering choices can lead to flawed products, especially when the people responsible fail to perform the most critical part of the design process and that is to put themselves in the shoes of their potential users.

Mike-Alpha-Romeo-Charlie, signing out.


Anonymous said...

Underlying problem: You came to the wrong planet. There is a one-syllogism max on all thought here.

Lukas Farley said...

Great blog, thanks for posting