HCDE Week 4 Process Blog

Week four of the class brought us the challenge of taking an already-created product and testing the user-interface for it, creating a set of challenges or trials for users that would help us to determine what worked and what did not with our given object. For our group, the item in question was an old coffee maker. So, what worked? What did not? It was time for us to find out.

The Black&Decker Cafe Noir, a machine that definitely does not life up to its title.

Setting up the Tasks

Our group decided early on that we wanted to have our challenges be key to the function of the machine as a whole, focusing on the things that needed to work fro the coffee maker to even function as a coffee maker. Early into the discussion we decided, as easy as it was, that turning the machine on and off again should be included. While this may be taken for granted as an easy task, we still wanted to include it to make sure it was an easy task. No point in the rest of the interface if the power switch has an issue, right?

By an extension of this line of thinking, we also settled on changing the filter as a task for our users, as just like turning the power on, being able to put a filter in the machine is an integral part of making it work.

For the final part of our test, we decided on using a sort-of fluff feature of the coffee maker: the clock. With the digital clock being a major part of the display, taking up a third of the total space, we figured it would be worth finding out if the clock was worth the room it was occupying by having the subjects change the time on the display.


For the test subjects, we wanted to have a mix of users who had used a coffee maker, and who had not; hopefully, should it all go right, the new users could work out the interface while the veteran users would be able to easily and efficiently work out the interface for this specific product.

A few of the ideas we considered when setting up the test

When taking data on the users, we wanted to get a variety of ways to quantify the experience, leading us to use multiple forms of data collection on each test. These included the time it took (to find the efficiency of the task), the number of mistakes made (to find out how confusing or intuitive the interface was), a response on a difficulty scale of 1 to 10 from the user (to get user input and also to provide feedback on the nature of the interface), and verbal comments from those being tested (so that they could provide in-depth feedback on the experience).

The Results

As was to be expected, turning the coffee maker on was (thankfully) easy, allowing us to quickly move forward with the testing of the more complex components of the interface. Not a single test subject found it at all difficult due in part to the “on” button being labeled in addition to a light alongside it that lit up when the machine was on.

Changing the time, however… proved to be significantly more difficult. While the clock does have a light that shows if the clock in in AM or PM, the light is small and hard to see unless your line of sight is level with the clock. As a result, all of the subjects failed to correctly set the time on the machine because they could not work out if it was set to AM or PM.

Replacing the coffee filter proved to be a mixed bag, as the user who had used a coffee machine before understood what to do right away, while the other users struggled with finding what to do. One user complained that the lever to open the coffee maker to access the filter needed a label, as this was the only moving part on the machine that did not have any sort of label on it. This was also the only trial to receive higher than a 5 in terms of difficulty, scoring an 8 out of 10 from the user mentioned above.

In Conclusion…

The test proved that, while functional, the Cafe Noir absolutely had room for improvement. Multiple users complained about being upset over not being able to work out how to operate the machine fully, even though the majority of the trials were based on basic functions of the machine. While the user who had prior experience with a coffee maker could operate it fairly well, our newer users struggled with making the machine work properly. That being said, the users seemed to understand what they did wrong when they found the solution, and would likely not make similar mistakes in the future should they use the product regularly. So while the Cafe Noir “does its job” in a loose sense, the interface could stand to be taken back to the drawing-board once more.

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