Water, water everywhere...

by Patty Lakinsmith

This one is for the "This Is Broken" usability file.

I found myself in an embarassing situation on a recent business trip. I was attempting to take a shower, and could not locate the control to redirect the water to flow to the shower head instead of the tub. I'm well traveled and have seen a lot of plumbing fixtures, but I was so perplexed by this one that I had to phone the front desk...or resign myself to taking a bath.

Here is the top part of the control.

Here is the bottom part.

Can you tell how to make the water come out of the shower head instead of the tub spigot? When the helpful front desk clerk explained it to me it was clear that they had a lot of calls on this one.

No fair peeking below.

Wait for it.

Wait for it.

OK, here's how it works.

Here's the answer - the bottom edge of the spigot pulls down to activate the shower redirect. Clever, huh?

This is one example of how population stereotypes can be very helpful. People expect certain frequently used controls, whether they are well designed or not. A light switch is one example (we expect them to flip up and down), water faucets another (I'll cover the temperature control on my Grohe kitchen faucet another time).

I'm sure that the designer of the faucet above was quite pleased that the mechanism to redirect the water was cleverly hidden, allowing the clean elements of the design to prevail. But how much money are these faucets costing the hotel chain that installed them? Every time a new guest stays at the hotel there is likely a call to the front desk to ask how to use it, which costs them in lost productivity. How many guests get annoyed, don't bother to call the front desk, and choose not to stay there again?

Sometimes a seemingly small user interface design decision can cause a chain reaction of events that ultimately cost a company money.

* * *

Dr. Lakinsmith is a senior scientist with Monterey Technologies, Inc., and has performed in a technical leadership role in a number of major commercial and government human engineering projects. She has applied user-centered principles and processes to the design and evaluation of both traditional and intelligent user interfaces on devices from screen-based telephones to critical cockpit systems.

Designing for Maintainability

by Tom Sharkey

One of my hobbies is racing motocross on vintage motorcycles. On one of my favorite motorcycles is a 1971 CZ 400, which was manufactured in Czechoslovakia. An important part of the off season maintenance on this particular bike is to clean, lubricate, and readjust the swing arm pivot. Without going in to a lot of detail, the swing arm fits between frame members and is held in place by a steel pin that passes though holes in the frame and swing arm. Tension is adjusted by tightening bolts that thread into the pin, which compresses everything together via a pair of cone washers. Figure 1 shows the basic configuration. This design was in use on this motorcycle from the early 1960s to the mid- 1970s.

Figure 1. Schematic of CZ swing arm setup.

As you can imagine, once the pin that passes through the assembly is taken out it is easy to disassemble the components so they can be maintained. Reassembly is not quite so simple, at least for one person, in large part because inserting the pin while positioning the swing arm and fitting the cone washers requires at least three hands. There are some tricks to make this easier, such as putting a dollop of grease on the cone washers to hold them in place and doing each side in series, but these are only marginally successful. The net result is that reassembly usually takes multiple tries as the cone washers drop off and fall on the work stand. While spending a few extra moments in the shop indulging in my hobby isn’t a terrible hardship for me, this is clearly not a design that had the maintainer in mind.

Jumping ahead four or five decades, I was recently asked to conduct a human engineering analysis of a new seat being designed for the military . This analysis was conducted from both the warfighter’s perspective and from the perspective of the maintainer, who happen to be the same person in the target user community. This seat is being designed to some demanding requirements including, but not limited to, weight, volume, adjustability, reliability, mean times to repair and replace, soldier survivability, and of course acquisition and life cycle costs. One of the requirements is that the seat back be removable and replaceable by a single maintainer in a very short period of time. Removal of the seat back is required to allow a maintainer to access other equipment more easily. Figure 2 shows the basic design of the attachment between the seat back and the seat base. Does this look familiar?

Figure 2. Schematic of military seat back-seat base junction.

Yes, the design being proposed for this new, state-of-the-art system is very similar to that found on my old motorcycle. One problem in the military seat design is the use of washers to eliminate lateral play between the seat base and seat back. Reinstalling these washers presents the maintainer with almost exactly the same problem as I find on the old motorcycle – how do you keep them in place while reinserting the pin that holds everything together with just two hands?

I tried to perform this operation in a nice warm, dry, well lit mock up of the military vehicle and indeed managed to drop the washers. Now imagine a military maintainer attempting to perform this task in a stressful environment, perhaps while wearing winter or other protective gloves. The outcome is likely to be dropped washers that aren’t found on the floor and consequently aren’t reinstalled. I should mention that in military systems of this type it is frowned upon to use a “dollop of grease” trick to hold the washers in place because the grease will collect dirt in the operational environment, becoming its own maintenance headache. It is also unacceptable to simply drop the washer on the floor and not recover it. There is no way of telling where the washer will end up and what the effect will be. For example, the lost washer could roll around on the floor and end up jamming the vehicle’s controls.

The bottom line is that by making a minor change in the design of the seat back that reduces the space between the seat’s base and back rest we can eliminate the need to use these washers, and alleviate the maintainability problems with the use of these washers in this venerable design. As a result of making the design change, one person can easily reinstall the seat back, the accuracy of the maintainers is increased (no washers are left out) and the time to replace the seat back after it has been removed is reduced, all of which are important metrics in the acceptability of the system. There are also cost implications. While improving the maintainability of a design to save a minute or two is of little consequence to a hobbyist working on a single machine, when hundreds or thousands of military maintainers perform a task repeatedly on their systems the cumulative time and cost adds up quickly. Now, if I could just redesign the old motorcycle I could spend a few more minutes riding.

Tom Sharkey is a senior scientist at MTI. He has over 25 years of experience providing human factors engineering support across a broad range of ground vehicle and aviation programs, both military and commercial. He is based in our Denver, CO office and can be reached at tsharkey [insert the at sign here] montereytechnologies.com.

Ethical Human Research and Your Company

by Patty Lakinsmith, Ph.D.
Is your user centered research and design company following the federal regulations pertaining to the use of human participants? If you're not, this recent story about a group of Cold War veterans filing a suit against the federal government should be a wakeup call. The regulations pertain to behavioral and social science research, as well as biomedical research, and what you don't know about them can hurt you and your chances of being funded in the future.

Six decades ago members of the military volunteered for experiments on "nerve agents, biological weapons and mind-control techniques", conducted by branches of the Department of Defense. They are now experiencing health issues, and are now sueing the government for failing to inform them about the nature of these experiments, and for failing to obtain their consent to participate.

Following numerous tragic incidents like these, in 1974 the National Research Act was signed into law and a Commission was formed to establish ethical principles guiding research involving human participants.

The Belmont Report summarizes the principles established by this law, which fall into the basic categories of Respect for Persons, Beneficiance, and Justice.

Respect for Persons means that individuals should be treated as autonomous agents, and second, that persons with diminished autonomy are entitled to protection. The concept of Beneficiance means that human subject should not be harmed, and further should serve to benefit from the research in which they participate. The principle of Justice suggests that all persons should be treated equally in receiving benefits or burdens from research participation.

According to the Code of Federal Regulations, Title 45, Part 46 (Protection of Human Subjects), any research conducted or supported by any Federal Department or Agency must comply with certain requirements for procedures, review, and oversight.

The regulation defines the term "research", and identifies what populations of individuals are protected, and those that are considered vulnerable in a research setting. The makeup and functions of an Institutional Review Board (IRB) are defined, and criteria by which an IRB will evaluate prospective research plans involving human subjects. Required elements of an informed consent form are listed, as are the rules governing the use of vulnerable populations such as pregnant women, minors, prisoners and the disabled.

Any entity wishing to conduct human research must apply for and hold an Assurance of Compliance, which is an official legal written commitment by an institution (private or public entity) made to the Federal Government to comply with the Federal regulations while conducting research with human participants. It outlines the procedures and policies in place with the research organization that will enable it to comply with federal regulations, and designates the Institutional Review Board that will oversee research proposals.

While you might think this doesn't apply to you since your work doesn't involve medical procedures, these regulations apply to behavioral studies as well. An IRB reviewing your usability study will be interested in how you recruit your participants, whether they belong to a vulnerable population (e.g. soldiers assigned to participate in your DoD study), how you explain what will happen to them in your study and solicit their consent to participate (and to be photographed or videotaped), the compensation, risks, and benefits given to your participants, and how you protect their anonymity. An IRB can review your plans and determine whether they fall into a low-risk category and are potentially exempt or eligible for expedited review.

Your ability to work efficiently and stay within the law while conducting research for a client is greatly enhanced by familiarization with these laws and revivew processes. Minor differences in a test plan can mean months less review time, and fewer hours spent in painful reviews.

We'll cover some of the key considerations for obtaining study approval in future posts.

Dr. Lakinsmith is a senior scientist with Monterey Technologies, Inc., and has performed in a technical leadership role in a number of major commercial and government human engineering projects. She has applied user-centered principles and processes to the design and evaluation of both traditional and intelligent user interfaces on devices from screen-based telephones to critical cockpit systems.