The range of users for a particular product or system.
E.2.2 Outline how large user groups may be defined.
Age - Eliminates other age categories, reducing number of unwanted people and data; useful for conducting research that targets specific age ranges. e.g. baby chairs
Gender - reduces type of person design for. e.g. preferences of females are looked into for the design of a Barbie doll
Physical condition - some products may be designed for physically disabled people. The type of disability may also be narrowed down as it is unnecessary to ask a person with limited hand movement when designing a wheelchair.
E.2.3 Outline the importance of sampling to gain information about potential users.
When considering a product design for mass use (e.g. water bottle) it is not good to rely on information from a small number of users, as it is unlikely to be representative of the whole range of users.
E.2.4 Describe how a user group sample is based on the factors considered in E.2.2.
It is necessary to consider the attributes of the user group when collecting a user group sample. Age, gender and physical conditions will be included during the sample.
e.g. it may not be helpful to know what boys think about girls toys as they won't be playing with them.
E.2.5 Discuss how the factors in E.2.2 are further defined to determine the exact nature of a user group sample.
Further definitions may be needed to obtain a more realistic idea about the group. This includes ethnicity and cultural background.
e.g. useful in designing airline seats; it is not useful to design seats for slim Asians for American carriers.
E.2.6 Outline the use of the concept of "methods of extremes" to limit sample sizes.
Sample users are selected to represent the extremes of the user population and intermediate values.
e.g. evaluating a kitchen layout may use the 5th percentile, 50th percentile and the tallest 97.5th percentile.
e.g. easy reach (vehicle dashboard/ shelving) 5th percentile; comfort/ posture 5th-95th percentile
E.2.7 Define population stereotypes.
Responses that are found to be wide spread in a user population
E.2.8 Describe the relevance of the use of population stereotypes in the design of controls for products.
Population stereotypes
If the design does not try to follow the population stereotype the product may be misused. This includes methods of turning on appliances, e.g. for fluids or gases the tap is rotated anti-clockwise, while clockwise is for mechanical products such as a radio.
E.2.9 Discuss the problems of displacing population stereotypes in the design of controls for products.
Population stereotypes can be displaced or overcome when alternatives are learnt.
E.g. on a plane, to release the seat belt the flap should be lifted, unlike the seat belt of a car where a button is pressed
E.2.10 Discuss how the use of converging technology in product design may lead to confusing control layout.
Combining technologies to improve or develop a product and be confusing for the user, because the different technologies may require a certain population stereotype, so operating the new product with converged technologies may confuse the user easily.
E.g. Cooking ranges (electric oven with gas stove)
Turning the knob for a gas cooker clockwise is 'off', this is because gas cookers are essentially taps. This is the same for the electric oven, hence a potentially dangerous situation is created if the user is confused and may switch the wrong function on.
E.2.11 Discuss how the concept of "range of sizes" and "adjustability" affect the design of products.
Range of sizes
The same product is produced in different sizes. Therefore a larger population group can use it.
The design should be able to be shrunk or enlarged, if this is not possible then the product can only be produced in one size and hence does not fit the requirements of a certain proportion of the population
E.g. Clothes; the range is from extra-small 'XS' (possibly XXS as well) to extra-large 'XL'.
Adjustability
Like 'range of sizes', this concept is aimed at increasing the user population group for the same product.
For this concept the product is created in a single size, however it can be adjusted to fit the requirements of the user. Elements that allow adjustability should be included, like enlargement straps.
E.g. Seatbelts are designed for the 5th to 95th percentile, and so it must be tailored to ensure the safety of the smallest to the largest person.
E.2.12 Compare the collection of static anthropometric data with the collection of dynamic anthropometric data.
Static anthropometric data
Data collected from a person when they are stationary. The person's dimensions are measured and recorded. The quantitative data is accurate and hence reliable.
Dynamic anthropometric data
Data collected from a person when they are performing a task, like reaching out a hand. This data would help designers in designing the use for something that requires the use of the hand/arm.
However this data may be unreliable, different researchers will have different methods of collecting data, so a variety of results may be obtained.
E.2.13 Describe the instruments used in the collection of anthropometric data.Sliding caliper
Measures the distance between two points accurately. Two measuring devices (position locators) protrude from the ruler. One is fixed at one end while the other is able to slide along the ruler.
The fixed locator is positioned at one point of the body that they want to measure and then the second locator is positioned at the second point. The measurement can be read off where the second locator is on the ruler.Stadiometer
Measures a person's height using a vertical ruler and sliding horizontal headpiece.
First the headpiece is moved up high, and the person then stands up straight below it facing out. The headpiece is then lowered gently until it rests on the head of the person. The height is easily read off the ruler.
Sitting height table
Similar to the stadiometer, but instead it measures the person's height when they are sitting down.
It also has a vertical ruler and a horizontal headpiece. This device is placed on a table not on the floor. First the headpiece is moved up high, and the person then stands up straight below it facing out. The headpiece is then lowered gently until it rests on the head of the person. The height is easily read off the ruler.
Measuring tape
Measures dimensions such as a person's waist circumference.
They are often flexible and can easily measure body parts that are not straight.
The metal tip at the beginning of the tape is held at one of the points, the tape is dragged along following the shape of the body until it reaches the second point. The distance is the number on the second point.
Torso callipers
Measures the width of a person's shoulder's or torso.
Operates similar to sliding callipers, but are larger.
Appearance and operation is similar to sliding callipers.
Harpenden anthropometer
Measures any linear length.
A sliding measurer runs on ball bearing rollers.
The slider's blades is placed on the points of the body that is to be measured. For example the length of a foot. The anthropometer can be extended using straight extensions.
E.2.14 Explain why it is difficult to obtain accurate anthropometric data using the equipment described in E.2.13.
Participants are required to removed certain articles of clothing for more accurate measurements. This may be awkward and difficult as many people may not want to be surveyed naked. So researchers often conduct the survey with clothed people.
E.2.15 Identify an appropriate percentile range for the design of adjustable equipment.
Adjustable equipment e.g office chairs, desks, should have a range of 5th (female) - 95th percentile (male). Females are usually smaller than males so the 5th percentile is from female data and 95th is from male data.
Multivariate accommodation (fitting in several variables)
Some designs include multiple anthropometric factors.
E.g. the passenger compartment of a car. The seat height, leg space, arm reach, viewing angles, hip breadth etc. all has to be considered.
Since everyone has different proportions, it is crucial to design for extremes of all data when designing systems or products that have multiple anthropometric/ergonomic factors.
E.2.16 Explain how designers use primary and secondary anthropometric data in solving a design problem.
Secondary data is less work, so researchers often look at that first. But because the information may not necessarily be suitable for the product.
E.g. American Airline looks at the secondary anthropometric data for the bust width of people, but the data is only the 'average' person.
Therefore, primary data would also be required because of the difference in size between the 'average' person and an average American.
E.2.17 Define biomechanics.
The research and analysis of the mechanics of living organisms.
E.2.18 Discuss the importance of biomechanics to the design of a given artefact.
Biomechanics is important as it includes muscle strength, hand size, surface texture and torque. These factors should all be considered in helping the product's ease of operation.
E.g. Opening a jam jar
Muscle strength and torque - different people have different output strengths, so designers should design for the weaker half of the population that can open a jar.
Hand size - the user should be able to grip the lid, or they can't even attempt to open it.
Surface texture - needs materials that encourage grip and has good traction, so users can easily open the jar.
E.g. Using a door handle
Strength and torque - a spring that is too strong would not allow the door to open. Old people do not have the same strong muscles as teenagers and everyone must be able to open the door perhaps to escape or just to access the room.
Surface texture - slippery handles are user-unfriendly
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