Sample Answers to Exercises and Thought Questions: Chapter 9
EX 9.1
What are some different ways you could communicate a concept for a new user interface for an automotive audio system? What are the strengths and weaknesses of each approach?
Here are at least four ways to communicate the user interface, with some strengths and weaknesses of each.
What are some different ways you could communicate a concept for a new user interface for an automotive audio system? What are the strengths and weaknesses of each approach?
Here are at least four ways to communicate the user interface, with some strengths and weaknesses of each.
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Strengths
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Weaknesses
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Textual description of how the interface would work, with a list of each input/output device and its function.
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May be useful to catalog the features and information associated with the user interface.
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Since the quality of a user interface is so dependent on the details of its layout and execution, this approach is not likely to result in an accurate test of usability.
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Two-dimensional layout of the interface (e.g., sketch or rendering on paper)
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Quick and inexpensive to prototype.
Useful way to articulate several alternatives. |
Will not be able to communicate key functional features of the interface.
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Computer simulation in which a computer mouse is used to control the input devices.
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Can test interaction (unlike sketches) with the user.
Easy to modify to test different versions of the design. |
Limited usefulness for testing physical ergonomics.
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Comprehensive prototype, both "looks like" and "works like"
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Very effective in testing the quality of a completed design.
May be the only way to test issues such as "ease of use with gloves on." |
May provide misleading results if the execution of the prototype is not very close to the production version of the product.
Expensive in time and money. |
Interestingly, this article (in the reference list for the chapter) uses an automobile audio systems as its primary example.
Ex 9.2
Roughly estimate N for the following products. List your assumptions.
Sleeping pillow for air travelers.
Assume that there are 2000 jumbo jets in service and that most sleeping pillows will be used on jumbo jets. If each jet makes on average two flights per day with an average of 300 passengers, then 600*2000=1,200,000 passenger trips are made each day on jumbo jets. Assume that 25% of these trips are during hours in which people would want to sleep. This leaves 300,000 passenger trips per day in which a sleeping pillow might be used. If we assume that on average, each passenger makes 4 trips per year, then there are 365*300,000/4 = 27,350,000 passengers in the world who could use a travel pillow. Based on observations of behavior on late-night flights, we assume that about 5% of these travelers own sleeping pillows, so the "installed base" is about 1.4 million. If the life of a travel pillow is five years, then the annual sales might be about 273,000 units worldwide. We could use this value for N if our estimated purchase probability is based on consumers who are shopping for a travel pillow.
An electronic weather station for homes.
We know that there are about 8 million homes in the United States with household incomes of greater than $75,000. These are the most likely purchasers of this product. If our concept test will sample affluent households and ask how likely they are to purchase within the next year, then N could be assumed to be 8 million.
TQ 9.1
Why do you think respondents typically overestimate the likelihood that they will purchase a product?
Most respondents do not have to actually pay cash to respond to the survey. It is much easier to commit fictitious money than real money. Also, most respondents seem inclined to want to please the surveying entity. Finally, rarely is a product placed right in front of a consumer. They generally have to actually seek it out, which may further erode the probability of purchase.
TQ 9.2
When might it not be advantageous to communicate the product concept to potential customers using a working prototype? Under what circumstances is it better to use some other format?
If the prototype is relatively clumsy or unrefined, it may be better to leave the product concept to the respondents imagination. Also, if there is substantial latitude in how the product concept may be implemented, then the team may not wish to bias the results because of an arbitrary choice of implementation.
- Vriens, Marco, Gerard H. Loosschilder, Edward Rosbergen, and Dick R. Wittink, "Verbal versus Realistic Pictorial Representations in Conjoint Analysis with Design Attributes," Journal of Product Innovation Management, Vol. 15, p. 455-467, 1998.
Ex 9.2
Roughly estimate N for the following products. List your assumptions.
- A sleeping pillow for air travelers.
- An electronic weather station (monitoring temperature, pressure, humidity, etc.) for homes.
Sleeping pillow for air travelers.
Assume that there are 2000 jumbo jets in service and that most sleeping pillows will be used on jumbo jets. If each jet makes on average two flights per day with an average of 300 passengers, then 600*2000=1,200,000 passenger trips are made each day on jumbo jets. Assume that 25% of these trips are during hours in which people would want to sleep. This leaves 300,000 passenger trips per day in which a sleeping pillow might be used. If we assume that on average, each passenger makes 4 trips per year, then there are 365*300,000/4 = 27,350,000 passengers in the world who could use a travel pillow. Based on observations of behavior on late-night flights, we assume that about 5% of these travelers own sleeping pillows, so the "installed base" is about 1.4 million. If the life of a travel pillow is five years, then the annual sales might be about 273,000 units worldwide. We could use this value for N if our estimated purchase probability is based on consumers who are shopping for a travel pillow.
An electronic weather station for homes.
We know that there are about 8 million homes in the United States with household incomes of greater than $75,000. These are the most likely purchasers of this product. If our concept test will sample affluent households and ask how likely they are to purchase within the next year, then N could be assumed to be 8 million.
TQ 9.1
Why do you think respondents typically overestimate the likelihood that they will purchase a product?
Most respondents do not have to actually pay cash to respond to the survey. It is much easier to commit fictitious money than real money. Also, most respondents seem inclined to want to please the surveying entity. Finally, rarely is a product placed right in front of a consumer. They generally have to actually seek it out, which may further erode the probability of purchase.
TQ 9.2
When might it not be advantageous to communicate the product concept to potential customers using a working prototype? Under what circumstances is it better to use some other format?
If the prototype is relatively clumsy or unrefined, it may be better to leave the product concept to the respondents imagination. Also, if there is substantial latitude in how the product concept may be implemented, then the team may not wish to bias the results because of an arbitrary choice of implementation.