When designing any kind of product it's important to be able to "get into the head of the user." A key to this kind of thinking is learning to observe how you and others interact with things. Donald Norman often used this approach in his classic book, The Design of Everyday Things. When I first read his book it changed the way I looked at things. Every once in a while, I'm particularly amazed by designs around me. Recently I recognized a few and what follows are three real world objects that I think are interesting from a usability perspective.
The Failure: Uni-ball Jetstream Pen
How can you ruin the usability of a pen? It's easy: make it so the user can't get to the ink-dispensing mechanism. Here's a picture of the Uni-ball Jetstream pen:
It looks innocent enough, but when I hand this pen to someone, they do the following, almost always in this order:
- Try to write with it, only to discover there's no pen tip exposed.
- Try to press the clip end with their thumb in hopes it will "click" to expose a pen tip. It doesn't.
- Try to twist the clip end hoping this will reveal the pen tip. It doesn't.
At this point, they will do one of two things: Look at me with an expression that says, "Okay, how does this work?" or they will try to pull the pen apart. If they pull hard enough, the cap will come off revealing the writing end and annoyed they will try to remember what they needed the pen for in the first place. Here's what the pen looks like without the cap on:
The user could be a child or adult anyone who wants to write or draw, but to succeed, they must discover the end which dispenses ink. Over time and through our experience with pens we have learned to identify which end of a pen is the writing end. This pen fails because the end without the tip looks like it should write and it doesn't. I think it's the metallic look and cone shape that suggest that it is the end you write with. These 2 simple design choices: shape and material provide a subtle hint that is strong enough to cause significant confusion if not failure in using the pen for its intended purpose.
How could this problem be fixed? The fix is to make the end that doesn't write look like it doesn't write. A change to the color so that it's not sliver would work. Another option would be to make the end cylindrical rather than conical. Either of these would fix the problem. I recently went to the store to see if I could get another pen like this one and I discovered they had changed their design, here's the new look:
The new version replaced the silver end with a black one, while keeping the exact same shape, but this small change significantly improves the usability of the pen. This example shows how even the simplest of tools, a pen, can be affected by poor usability design. It also shows how even the smallest design change can make an object that was frustrating to use, so usable it simply disappears.
The Marginal Success: In-Sink-Erator Pro 17 Disposer
A marginal success is something that the targeted user is likely to be successful using, but due to various constraints, it is not living up to its potential. The awesomely named "In-Sink-Erator" disposal in my kitchen falls into this category.
A kitchen disposal is used to grind up bits of food that might plug up your kitchen sink drain or worse: the pipes leading to the sewer. During the normal use of a kitchen sink, leftover food inevitably ends up in the sink. Without the disposal, the user must carefully remove the messy food scraps and throw them into the trash by hand. Because a disposal is composed of mechanical blades that move at high speed, it is a dangerous device. An arrant utensil sent "down the drain" while the disposal was running could harm the machine or user or both. Care must be taken because almost all family members--children and adults--could be interacting with the device.
Does anyone see a problem here?
The on/off plug switch and stuck food.
The drain plug rotates either left or right to turn on and off the disposal. When it's on, there is only a small opening around the plug that lets water through. The plug has 3 functions: 1) turn on and off the disposal, 2) keep hands, utensils, etc. out of the device while it is on, and 3) plug the drain entirely so you can fill the sink with water. All of these are fairly easy to discover and accomplish with rotation of the plug at different levels.
The real advantage of this plug-activated design is that it is impossible to turn on the device and accidentally drop anything into it while it is running. This is a great safety feature, but it comes at a cost. First, the user must reach down into the wet sink to turn on the unit at the very least getting his or her hand wet. This means that before going onto another task, hands will need to be washed and dried again. Second, the opening on the plug is small, which means it gets clogged, filling up the sink. To fix this the user must reach down, turn the plug and pull it out to allow the water to drain. As the water rushes in the disposal cavity the air must escape and as it does, it sprays the user with dirty water. Using this disposal is always safe, but potentially very messy.
Certainly the user doesn't want to lose a finger or bend a fork in the disposal blades, but neither does the user want to get dirty while rinsing dishes in the sink. This device does its job, but the constraint of ultimate safety is at odds with the users immediate goals and makes the device less enjoyable to use.
An alternative solution would be to, have the switch that turns on and off the disposal without the need to reach down into the murky water. For additional safety the switch could be located in a place that requires the user to step away from the sink just enough that if something was ejected from the disposal, like a spoon that had escaped down the drain, the user would be out of range. A single purpose plug could be provided to fill the sink when needed. Rubber baffles around the drain could minimize splashing. This is a compromise on safety, but I think it's the better compromise since the users goals are more focused on cleaning and draining the sink.
This example shows how important it is to design with the context of the user in mind. Their context can expose their goals and desires. It also shows that in an effort solve one problem, you can create secondary and unintended side effects that can be worse than the original problem being solved. Great restraint must be used to avoid this pitfall. Not every problem is worth fixing.
The Runaway Success: Dodge Grand Caravan Door Handle
Finding a "Runaway Success" in usability can be difficult because they tend to be invisible. They are so easy to use that it is difficult to imagine that they could be designed in any other way. My Grand Caravan door handles fall into this hall of fame category.
Obviously the external door handle is used to open the door. That is the user's goal. Young or old, tall or short, all who want to enter the car must first open the door.
This is a successful design for several reasons. First it's simple. You see the door and you know how to use it: you pull and it opens. The handle that you grab onto hinges out mimicking the way the door opens. The keyhole is placed next to the handle and relates to and inhibits the handle hinge movement when locked. You can operate the door from below, for example in a wheel chair or a child's height or standing. In a rescue situation a solid handle provides a clear place to securely pull on the door. When in the dark because the door handle material is a different color and is not flush with the door, you can easily find the handle, and once you have found the handle, you have also found the keyhole for unlocking the car. Also, because the handle is a durable plastic, your constant opening of the door minimizes scratched the paint.
There is one thing that could be better in the sliding door handles. The sliding doors slide back away from the front door, but the hinge on the handle swings forward, not back. This makes sense for when closing the door, but not for opening the door and closing the door is easier than opening it in most cases and often done from the inside of the vehicle. My children regularly can't get the door handle open because they are pulling back toward the rear of the car and are not able to achieve sufficient outward pull on the handle. If the hinge on the handle would follow the opening of the door like in the front doors, this problem would be eliminated.
We can learn from the good and bad all around us, but we must take the time to observe. This skill of careful observation is a key to better understanding, compassion and humility when designing something truly usable. Great usability begins with what we see.