All posts by Anne McLaughlin

Associate Professor, Department of Psychology, North Carolina State University, Raleigh, NC

The Double-Bubble Ballot

U.S. news agencies are reporting on the California ballots that ‘may have lost Obama the California primary.’ The argument is that he would have pulled in the ‘declined to state’ voters (those who have not registered as either Democrat or Republican), but that because of a human factors error with the ballot, those votes may not have been counted. (The inference is that these voters would have supported Obama.)

Succinctly, declined-to-state voters have to ask for a Democratic ballot. Then they must fill in a bubble at the top of the ballot, saying that they wanted to vote in the Democratic primary. Obviously, many users might not do this, as it seems a redudant code… the ballot they are holding is the Democratic ballot, so why indicate again that it was the ballot they requested? If you look at the ballot below, it says at the top to “select party in the box below.” Of course, there is only one option, which makes it not much of a selection.

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It’s likely this area of the ballot was inserted to produce some interesting statistical information (rather than a pure answer of who received the most votes.) If only declined-to-state voters filled the bubble, you could get a count of how many of those voters came out to vote compared to other years, how many chose to vote Democrat, and which candidate received most of their support. While interesting (I would like to know all of those things) it complicates the purpose of primary voting: to count the number of Americans who support a particular candidate.

Why I am not a conspiracy theorist: People with the best of intentions make critical human factors design errors, even errors that cost people their lives (see “Set Phasers on Stun.”) Sometimes, these errors are created by specific good intentions, as in the Florida hanging-chad fiasco.

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The reason the choices were staggard on each side of the ballot was to increase the font size, supposedly making the ballot more clear for older voters. This perceptual aid was trumped by the resulting cognitive confusions. These ballot designs may suffer from a lack of user testing, but not from an intentional ploy to keep declined-to-state voters from being counted or to get Pat Buchanan more votes.

Thus, let’s tackle the problem rather than using ‘double bubble’ for a slow news day. Why don’t we demand all ballots and voting machines be user tested? (Security is another issue, for another blog.) If you have an idea of what action to take, please comment so a future post may provide detailed instructions.

Welcoming the Fireproof Elevator

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NPR ran a story earlier this week on an intriguing new human factors problem: fire-safe elevators.

The fall of the World Trade Center made it painfully obvious that stairs in skyscrapers do not function adequately in emergencies. We’ve always been warned away from elevators in case of fire, and I would go so far as to say it part of our collective knowledge from a young age. With the advent of elevators you should use in a fire comes a host of difficulties.

1. Training the zeitgeist: Not all elevators will be replaced, though new tall buildings will all have fireproof elevators. There may be new rules requiring older buildings over a certain size retrofit at least one elevator as fire safe.

  • This still makes fireproof elevators the exception instead of the rule. A great research question would be how to train people for a small-percentage case? You want the public, of all ages and experience levels, to know “In case of fire, use stairs, unless there is a fireproof elevator around, which you may or may not have noticed while you were in the building.”

2. Warnings and Information: The symbol in this post is probably familiar to all of you. I’ve occasionally seen it in Spanish, but not often. How will we indicate the difference between fire-safe elevators and other elevators?

  • Decals, signs and other indicators will not only have to indicate which elevators are safe and their purpose, but whether other elevators in the building are safe or unsafe. My building is square, with elevators on mirrored sides. If one were safe and the other not, I am sure I could remember which was safe, especially under the cognitive demands of an emergency.

3. Wayfinding and luck: Use of the elevator may depend on the location of the fire.

  • One of the original problems was that elevators opened onto smoke-filled or fire-filled floors. The story did not specify how the new elevators would avoid this. If there is a sensor that prevents them from opening onto such a floor, what if there are people desperately waiting for the elevator on that floor (as they have been re-trained to do)?
  • Should the system be even more complex, with people gathering on certain floors to await the elevator rescue? And then, if those floors are on fire..

In short, researchers start your engines! We have some training, warning, design, and way-finding work to do.

NPR covers a good bit of the HF field in one conversation with two doctors

All Things Considered interviewed Dr. Peter Pronovost this weekend about the checklist he developed for doctors and nurses in busy hospitals. On a topical level, this illuminated the working memory demands of hospital work and statistics on how easy it is to err.

As an example, a task analysis revealed almost two hundred steps medical professionals do per day to keep the typical patient alive and well. On average, there was a 1% error rate, which equates to about two errors per day, per patient.

Pronovost introduced checklists for each type of interaction, which resulted in Michigan hospitals going from 30% chance of infection (typical across the US) to almost 0% for a particular procedure.

Could something as simple as a checklist be the answer? No, because this intervention wasn’t “just” a checklist.

Whether trained in these areas or not, the doctors interviewed had to understand:

Team training: Nurses are trained not to question doctors, even if they are making a mistake. Solution: Pronovost brought both groups together and told them to expect the nurses to correct the doctors. (Author note: I’d be interested to see how long that works.)

Social interaction: In an ambigous situation, people are less likely to interfere (e.g., the doctor didn’t wash his or her hands, but the nurse saw them washed for the previous patient and thinks “It’s probably still ok.” Checklist solution: eliminate ambiguity through the list.

Effects of expertise: As people become familiar with a task, they may skip steps, especially steps that haven’t shown their usefulness. (e.g., if skipping a certain step never seems to have resulted in an infection, it seems harmless to skip it). Checklist solution: enforce steps for all levels of experience.

Decision making: People tend to use heuristics when in a time-sensitive or fatigued state. Checklist solution: remove the “cookbook” memory demands of medicine, leaving resources free for the creative and important decisions.

Design out, Guard, then Warn

Check out this fascinating solution to protecting users from the blade of a table saw.

The way it works is that the saw blade registers electrical contact with human skin and immediately stops. I can’t imagine not having this safety system in place, now that it is available. However, I still have some questions that commenters might want to weigh in on:

1. Unless the system is more redundant than an airplane, it must be able to fail. How do you keep users to remain vigilant when 99.999% of the time there is no penalty for carelessness?

2. To answer my own question, is the fear of a spinning blade strong enough to do that on its own? I know I’m not going to intentionally test the SawStop.

3. Can we use natural fears such as this in other areas of automation?

4. For great insight into human decision making, read this thread on a woodworking site. What would it take to change the mind of this first post-er?

When do we as adult woodworkers take responsibility and understand the dangers of woodworking. Most accidents happen due to not paying attention to what we’re doing. If we stay focused while we’re using power tools, or even hand tools, we eliminate accidents.”

Intuition vs Experience with Roundabouts

Some people might say a traffic circle is obvious. There is only one way to go.. who yields might be more difficult, but at least we are all driving in the same direction.

Not so.

The following two articles come down on the side of experience for the usability of roundabouts.

New Traffic Circle Causes Confusion

Death-crash car launches off the road and into a first floor flat

I am sure the designers believed that if millions of people in London and hundreds of thousands in New Orleans can handle a roundabout, these citizens of a town so small they don’t even bother to mention where it is would do fine.

Why Human Factors is more than providing safety equipment

The new math and physics building is going up outside my window at North Carolina State. I see the workers out there each day, and as the building gets higher they are obviously required to don different safety gear.

The fuzzy picture below shows two workers on the top level (7th floor) and the green highlight is my outline of the full body harness and safety cord the man is wearing. Indeed, it seemed necessary as whatever tool he is using seems to push him off balance with every use (some sort of nail gun?)

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However. Unlike the man behind him, this worker has not attached his safety cord to anything. It merely drags along behind him as he walks around the platform and crawls in and out of the scaffold. In fact, it seems to get in his way when the clasp on the cord catches on the corrugated surface of the platform.

Team Training

Enjoy this video of expert team performance. I note that the post-er says these Marines “cut a lot of corners.” I’d be very interested to know how this differs from what they “should” be doing and what is optimal.

This from comments on the video: “Chief, what are you doing?! That was one jacked up fire mission. Are you trying to get your guys killed in a training mission? Not swabbing the breach or checking the bore while firing slow burning greenbag?! And what are you doing in the way between the trails? Didn’t do FCATS, did you? Don’t trust the quadrant on the gunner’s side?”

Legal Interpretations can be the Bane of Good Human Factors

Verizon wireless interpreted an accessibility requirement to require they trigger a notification when the user dials 911. Verizon chose to do this audibly… exactly what you DON’T want when you’re calling the police during an emergency!

“The tone our customer experienced is our interpretation of Section 255 of the Telecommunications Act calling for a provider of telecommunications service to offer service that is accessible and usable by individuals with disabilities. The tone, indicating that 911 has been dialed, is one of several features designed to make wireless service is accessible and easy to use, especially for those with disabilities. Other features include a voice command key where customers can use their voice to dial by name or number; a voice echo feature so that a person who can’t see can hear the number or letter if sending a text; read back text messages and speech output of signal strength, battery strength, missed calls, voicemail, roaming, time and date.”

Read the full news article here.

Perhaps there was no time for use cases or personas. “Debbie sees 4 masked men breaking into her home. Trapped, she hides in the closet and dials…. oh. Wait, guys. I think we have a problem.”

“From the Doctor’s Brain to the Patient’s Vein”

It appears that HFB needs an entire section devoted to medical error. This is not surprising in light of the thousands of Americans who die from preventable errors each year.

The latest comes from Tanzenia where confusion about patient names earned brain surgery for a twisted knee, and knee surgery for a migraine sufferer.

Mr Didas who had been admitted for a knee operation after a motorbike accident is still recovering from the ordeal – he ended up unconscious in intensive care after his head was wrongly operated on. And chronic migraine sufferer Emmanuel Mgaya is likewise, still recovering from his unplanned knee surgery. The blunder was blamed on both patients having the same first name.
But a hospital official, Juma Mkwawa said it was the worst scandal that had happened at Muhimbili hospital and that, “sharing a first name cannot be an excuse”. The two surgeons responsible have been suspended. (BBC)

Before anyone retreats into the comfort of “that wouldn’t happen here,” I suggest a look at the growing literature on similar medication names and their consequences.

It is easy to be the bearer of sad stories and ill tidings. I would rather on a note for a hopeful future. Below are researchers and companies dedicated to identifying and eliminating causes of medical error.

Please add more in the comments section if you know someone working in this important context.