PACT

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PACT is a framework used to analyze design situations. It operates under the priciple that "//People// use //Technologies// to undertake //Activities// in //Contexts//". When designing interactive systems, one needs to understand how each element varies and how they affect one another.

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**//People//**
Who are the users of the system? What characteristics do they share? Designing a keyboard for a child is different from designing a keyboard for an older adult because the two user groups differ in various ways. People are not all the same, they come in different shapes and sizes.

Example: Early Japanese cars, made for generally small people, did not work in North America. Example: Braille on ATMs, regular car steering versus power steering requires much more effort and strength.
 * //Height/Weight// - People come in many different sizes. Although it may be impossible to cater to all existing dimensions, designers should aim to accomodate as many users possible. The average size of a child's hand is different from the average size of an adult's hand. Therefore, the children's keyboard would probably need to be smaller in size than the adult's. Some designers may use an [|anthropometrics table]as a guideline for the dimensions of their design.
 * //Physical Abilities// - This includes strength and perceptual abilities. Older adults may have poorer visual acuity and poorer finger control. This means their keyboard may need to display larger letters with higher contrast. The buttons may also need to be harder to push to prevent accidental keystrokes. Also disabilities such as a being deaf or blind.

//Psychological/Social Differences//
Example: ATM select a language
 * //Language and Cultural Variety -// Not only do people differ in the languages they speak but also in the cultural conventions they apply to certain situations. This includes social cultures as well as international cultures. For example, in Web culture, an unvisited link is usually indicated by blue highlighted text while an unvisited one is anything other than blue (usually purple). This is so widely understood by those in the Web culture that many expert website guidelines recommend sticking to this convention for accessibility reasons: http://www.useit.com/alertbox/20040510.html. Other colours can work for links as long as the visited link is a more saturated, washed out shade of the unvisited link so users can see the relation easier (Nielsen, 2004).
 * //Learning Styles -// People have different preferences in the way they learn. Some learn better when information is presented to them spatially, logically or visually. Howard Gardner proposed that there are actually multiple types of intelligences and that each person has varying skill in each type. These multiple intelligences were divided into Visual, Linguistic, Logical & Mathematical, Musical, Kinesthetic, Naturalistic, Interpersonal and Intrapersonal. In a new design it may be important to accomodate for people's varying levels of learning styles. For example, a more compact, factual input system (lists and option buttons) may be appropriate for those with more skill in logical thinking while a more open-ended input system (textboxes and comment boxes) may be appropriate for those with more skill communicating with words.
 * //Attention, Memory and Mental Models -// what it is suppose to be like (conception)

= = //Use Difference//
 * Novice users – usually need to be guided through the use of the system
 * Experienced users – use the system regularly and usually know numerous functions in detail
 * Discretionary users – people that don’t necessarily need to use the system and are easily put off if it is difficult to use or understand.
 * //Organizational/Broad Social Contexts -//



//Activities//
The most important thing in activity is that the desinger has to focus on the overall "purpose" of the activity.


 * Temporal aspects**
 * designers should make sure the frequent tasks are easy to use and control. Ex, changing the cellphone battery.
 * infrequent tasks are easy to learn and remember.
 * system should work well at all times - under time pressures, slow periods, busy periods, etc.
 * design needs to ensure that a user can start where they left off of an action and make sure that the user does not leave out important steps. For example, document processing programs. Workers are always being interrupted by other colleagues, phone calls etc. If a worker leaves their desk or has to do something else on the computer, they should be able to come back and continue where they left off. Also the design should tell them whether or not they have left out any steps.
 * the response time of the system should be as short as possible since we live in a fast-paced world and people like to see results immediately or the system may be needed for an emergency. Generally, for hand-eye coordination tasks, expected response time is 100 milliseconds and for cause and effect actions, expected response time is one second. Response times longer than 5 seconds get users frustrated.


 * Cooperation**
 * tasks that cannot be carried out alone need to take into consideration communication and coordination with other people and technologies.


 * Complexity**
 * the task that the system needs to accomplish strongly influences the design.
 * Complex tasks need specific components for input and output. For example, a specific document processing program is needed for different types of documents and each program has a specific step-by-step design. This task may also require a specific printer for the document.
 * Simple/vague tasks require less specific components. For example, a computer for browsing the internet. The user only needs the basic components of a computer to carry out this task.
 * Safety-critical**
 * some activities are safety critical meaning that any mistake could result in a serious accident or injury. The design should ensure that mistakes do not have a big effect. For example,
 * the designers should keep in mind what happens when mistakes happen and design for such situations. For example, when people click on certain thing on a computer by accident, such as delete an item, the computer confirms this action by asking the user if they are sure they want to carry out this action.


 * The nature of the content**
 * the type and form of the data inputted and outputted by the system have different requirements. For example, entering large amounts of numeric and alphabetic data will require a keyboard. Or high resolution output might require an expensive screen.
 * some activities require certain media. For example, printing a document will require a very different printer design than printing a high resolution poster.

(Benyon et al 2005)



Context
Context refers to either the situation or surrounding activity or the factors which stick all the activities as a whole. There are 3 types of contexts:


 * Physical environment**- The geographical location and climate needs to be taken into account. Whether the climate is hot, dry sunny or cold, wet and windy this needs to be taken into account. For example, if a card cannot be read under light in a tropical country then it does not fit the context of the people who live there.


 * Social context**-social norms and practices dictate what is useful for the people in a particular setting. For example,something slow and full of sound will not be appropriate in the workplace whereas if one is alone that is acceptable. Access to helpers, experts and other people are relative from place to place and this needs to be considered.


 * Organizational context**-the impact of technology on each organization differs and depends on the job environment, time and place. Changes in technology can affect employment and blue collar workers who lose their jobs if technology replaces what they do.



//Technology//

 * Input** - devices involved with entering data and instructions into a system. The type of data that needs to be entered greatly influences the input method. For example, a keyboard would be needed if there is a lot of information that needs to be entered into a system, such as document processing systems.


 * Output** - device that displays the output of systems and depends on the type of output. For example, a display screen would be needed if the output was visual, such a videos. Text output could just be printed and given back to the user.


 * Communication** - bandwidth, speed and feedback to the user are the main issues that need to be handled. Without feedback, people would not know if the system has done anything with their input and the user would become agitated and frustrated.


 * Content** - for some technologies, this is the most important feature, therefore, it should always be up-to-date, accurate and relevant. For example, the stock market website. Stocks are always changing and people access the website to see current stock prices. Out-of-date stock prices are of no use to anyone.

(Benyon et al 2005)

__Anthropometric Notes.__ Onine at: [|, consulted on October 10th, 2006.

Benyon, David, et al. __Designing Interactive Systems__. England: Pearson Education Limited, 2005.

Fabio, Darleen. __Howard Gardner's Multiple Intelligences__. Online at: , consulted on November 7th, 2006.

Nielson, Jacob. __Design Guildelines for Visualizing Links__. Online at: [|, consulted on October 10th, 2006.