Paper
Prototyping
Primary Reference Source
Rettig, M (1994) Prototyping for tiny fingers. Communications of the
ACM, April, Vol.37,No.4.
Summary description
This method features the use of simple materials and equipment in order
to create a paper-based simulation of an interface or system. Paper prototypes
provide a valuable and cost-effective means to evaluate and iterate design
options before a team gets committed to one implementation. Interface elements
such as menus, windows, dialogues and icons can be sketched on paper or
created in advance using card, acetate, pens etc. The result is sometimes
referred to as a low-fidelity prototype. When the paper prototype has been
prepared a member of the design team sits before a user and ‘plays the
computer’ by moving interface elements around in response to the user’s
actions. The user makes selections and activates interface elements by
using their finger as a mouse and writing ‘typed’ input. A further person
facilitates the session by providing task instructions and encouraging
the user to express their thoughts and impressions. Notes may be made by
other observers or a video record may be created.
Typical Application Areas
The method has wide applicability. However, it is most suitable in contexts
where it is easy to simulate system behaviour or when the evaluation of
detailed screen elements is not required. Paper prototyping is appropriate
for the early stages of the design cycle where changes can be readily made
before there is a commitment to one implementation.
Benefits
Usability problems can be detected at a very early stage in the design
process (before a commitment to code has been made).
Communication and collaboration between designers and users is encouraged.
Paper prototypes are quick to build and refine, and thus support iterative
design and multiple evaluations.
Only minimal resources and materials are required to convey product
feel.
The technique can be utilised by those with little or no human factors
expertise.
Limitations
Because of their simplicity, paper prototypes do not support the evaluation
of fine design detail.
Due to the use of paper and a human operator, this form of prototype
can not be reliably used to simulate system response times.
The individual playing the role of the computer must be fully aware
of the functionality of the intended system in order to simulate the computer.
Cost of use
The technical resources required are minimal. Materials such as paper,
card, adhesives and markers are needed to create the actual prototype.
In addition, some means of recording the interactions between user and
prototype is required (e.g. video camera). The method also needs one individual
to play the role of the computer or system, and another to act as a facilitator.
Costs may also be incurred when recruiting users and allocating time to
manage each evaluation session.
Costs of Acquisition
Compulsory training is not specified although the method may require some
degree of training in order to acquire the basic skills.
Suitability for requirements engineering in Telematics:
This method has a role in RESPECT and is perhaps one of the most accessible
approaches to prototyping.
How to get it
Some RESPECT partners
are able to offer courses and hands-on experience.
Detailed description of method
The following material outlines firstly a general procedure for implementing
this method, and also indicates the kind of information that is produced.
Then a more detailed overview of two activities that can be carried out
with paper prototyping is given: sketching and user testing.
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Firstly, allow enough time to create the prototype, design some tasks,
recruit users, conduct the evaluation of the prototype and report the results.
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Assemble the necessary materials. Construct the paper prototype, using
separate stock for menus, dialogue boxes and any element that moves or
changes appearance.
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Select appropriate users to test the prototype, try to cover the range
of users within the target population.
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Prepare realistic task scenarios for the evaluation.
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Pilot the evaluation procedure and practice playing the role of the computer.
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Ensure recording facilities are available and functioning.
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Conduct each session, by manipulating the paper prototype as the users
work through the tasks.
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The facilitator provides the task instructions and explores the user’s
impressions and intentions through appropriate questions.
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If observers are present they can make notes of problem areas and potential
solutions on cards during the session for later scrutiny and prioritisation.
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Conduct post-session interviews with the users, drawing upon pre-set questions
and issues raised during the prototype evaluation.
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Debrief the users and thank them for their co-operation.
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Analyse information obtained, summarise observations and user evaluations.
Consider the themes and severity of the problems identified.
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Summarise design implications and recommendations for improvements and
feed back to design team. The video recordings can support this.
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Where necessary refine the paper prototype and repeat the above process
The evaluation of paper prototypes provides an opportunity to collect early
design feedback. This results in recommendations for the refinement of
the initial prototype, which can form the basis for the evaluation of further
prototypes.
Sketching
This technique involves members of the design team and potential users,
producing sketches or designs of the ideas that they wish to input to the
design process. The objective is to enhance user participation in the design
process and collaboration between designers and users. The easiest way
to set up a sketching exercise is to use a flipchart or whiteboard with
everyone sitting around it presenting and reacting to ideas. An electronic
whiteboard has the advantage of producing printouts of the ‘screen’ which
can then be photocopied to the group before rubbing out the earlier ideas
to consider new ones (e.g. SILK Landey 1994). Alternatively, users may
sketch their own ideas individually which they can then each present in
turn to the group.
A more sophisticated method involves presenting users with a set of
paper, cardboard or plastic interface elements which they can lay out,
on a flat surface, in what they feel is an appropriate way. Again designs
may be discussed and developed as a group or individually. An example of
such a kit is PICTIVE created at Bellcore by M. Muller (1992). This method
is effective when the basic control types of a future interface are known
but user feedback on a suitable layout is required. The method does not
require users to draw the interface although they can supplement the design
with additional elements or annotations to add contents.
The success of the exercise relies on the presence of a facilitator
chairing the meeting. The main role of this person is to ensure that the
group stay focused upon the design problem and ensuring that every member
of the group is given the opportunity to stand up and present his or her
own ideas. Another role is to summarise all the ideas after the session
for presentation to a design team meeting.
The outcome of a participatory design exercise will be a series of ideas
for screens, layouts, navigation structure, that can be evaluated by the
design team to assess their technical feasibility and usability. They will
thus serve as a first draft of design specifications. Various techniques
are possible to preserve the designs : the sessions can be recorded on
video, the paper mockups may be stuck down onto a base sheet, covered with
clear plastic, photographed or simply photocopied. They may then be mocked-up
on screen or in hardware form to further test the ideas. The paper screen
designs can also be used as a ‘walk-through’ exercise to get reactions
from other end users.
User testing
Early pilot studies of a system idea can be carried out using paper versions
of screen displays. These tests can be run to compare design alternatives,
or to contrast with current procedures. The paper-prototype should be designed
to contain the screens or interactive sequences needed to perform a series
of typical tasks. During the test, a member of the design team sits in
front of a user and ‘plays the computer’ by moving interface elements around
in response to the user’s actions. Alternatively they may write messages
on ‘post-its’ to represent elements such as pull down menus or dialogue
boxes. The user makes selections and activates interface elements by using
their finger as a mouse and writing ‘typed’ input. A further person facilitates
the session by providing task instructions and encouraging the user to
express their thoughts and impressions. Notes may be made by other observers
or a video record may be created.
A variant of the paper walkthrough is to produce the screens as a set
of cards. Users are asked to order the cards in the sequence that seems
most appropriate for the activities they must carry out. The objective
is to focus on the flow of user tasks and identify the appropriate structure
of the task-sequence. (e.g. CARD: Collaborative Analysis of Requirements
and Design, M.Muller 1992). Cards may also be used to elicit data or menu
structures from the user. Each of the data elements or menu options may
be written out on cards and laid out infront of the user. The user then
places the cards into piles to represent suitable groupings. Common groupings
between different user subjects can be used to structuring the system data
or menus.
The method is particularly useful for assessing user reactions to layout,
data structures, and sequencing of screens. However it is hard to convey
to the user the feeling of interacting with the new system.
The tests allow usability problems to be detected and recommendations
be made at a very early stage in the design process, before a committing
the design to code. Thus it supports iterative design and multiple evaluations.
Further redesign can be carried out on paper, or the design can be developed
on screen to test the dynamic interactive features.
References
Landey J., (1995) Interactive Sketching for User Interface design Proceedings
of ACM CHI 95 Conference pp.63
Muller, M. J. (1992) Retrospective on a year of participatory design.
Proceedings of ACM CHI 92 Conference pp.455
Remington R.,(1994) CHIRP : The computer human interface Rapid Prototyping
and design assistant toolkit. Proceedings of ACM CHI 94 Conference pp.455
Rettig, M (1994) Prototyping for tiny fingers. Communications of
the ACM, April, Vol.37, No.4.