prototyping lesson 05, Lecture notes of Wireframing and Prototyping

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Prototype Evaluation

Lesson 4

Introduction

• (^) Prototypes evaluation is a critical part of the prototyping process and there are two parts of prototypes evaluation – - User evaluation and - (^) Expert Evaluation There are many User evaluation techniques including surveys, focus groups, application usage feedback, ethnography observations etc. One of the most effective methods of user evaluation of prototypes is – Protocol Analysis.

The technique of Protocol Analysis

includes the following steps –

• (^) Identification of the Subjects
• (^) Identification of Task
• (^) Instructions to Users
• (^) Execution of Protocol Analysis
• (^) Post Task Interview
• (^) Analysis

4.2. Cognitive Walkthrough

(Norman’s Model)

• (^) The Norman’s model of human action provides a sound yet simplified theoretical framework of 'design and evaluation. It allows the definition of some basic cognitive steps in the analysis of human interaction with artifacts. The model describes five states (goal, intention, action, perception, evacuation) and three distances:

4.3. Communicability Evaluation

• (^) Prates, Barbosa and de Souza [2000] propose a method of communicability evaluation is a method based on semiotic engineering that aims at assessing how designers communicate to users their design intents and chosen interactive principles, and thus complements traditional usability evaluation methods.
• (^) The process that was defined for this included the following steps:

Tagging

• (^) Tagging is the process of relating a sequence of interactive steps to an utterance (from a predefined set), in an attempt to express the user’s reaction when a communication breakdown occurs. The tags used in communicability evaluation were identified based on literature about explanatory design.

Semiotic Profiling

• (^) In the semiotic profiling step, the evaluators proceed to interpret the tabulation in semiotic terms, in an attempt to retrieve the original designer’s meta-communication
• (^) that is, the meaning of the overall designer-to-user message. A semiotic engineering expert, due to the nature of the analysis, should perform this step.

Semiotic Profiling

• (^) The communicability method not only identifies problems, but also gives the designer hints to a solution. The utterance category narrows down the possible causes of the problem and the tagged pieces frequently provide the designer with evidence of the users intuitions about a solution.
• (^) By identifying interface elements whose meaning users were unable to grasp (missing of affordance) the designer may choose to represent those elements differently.

Some of the methods used for expert reviews are

• (^) Heuristic Evaluation: The application is compared to some standard interface guidelines like Scneiderman’s eight golden rules.
• (^) Guidelines Reviews: The interface is checked for conformance to the organizational guidelines for interface design.
• (^) Consistency Inspection: The different parts of the prototype are evaluated for consistency of color, layout, terminology etc.
• (^) Cognitive Walkthrough: The experts stimulate the users walking through the application and try to understand the regular usage cases along with exception handling

4.5. User Participation

• (^) User participation is central to the process of prototyping. Users are expected to commit as much to development of the prototypes as the software development team.
• (^) Bowers, Pycock [1994] did a study of multiple transcripts user- designer design process and made the following observations:

User Participation

 User participation in design can be characterized as meeting between two ‘language games’ (that of the designer and that of the user’s world of work)

• (^) Close relations between designers and users in work-like settings are not itself enough
• (^) There should be encouragement of reflexive participatory design in which both designers and users can become aware of the means by which requirements are interactively produced.

User Participation

• (^) Harker [1993] did a study of a large distributed system development and reported three issues relating to the use of prototyping as a part of user centered strategy are worth considering.

Rapid Ethnography

• (^) Millen [2000] introduced "rapid ethnography" which is a collection of field methods intended to provide a reasonable understanding of users and their activities given significant time pressures and limited time in the field.
• (^) Fundamentally involves limiting or constraining the research focus and scope, using key informants, capturing rich field data by using multiple observers and interactive observation techniques, and collaborative qualitative data analysis.

Experience Prototyping

• (^) "Experience Prototyping" [Buchenau, Suri. 2000] can be described as a form of prototyping that enables design team members, users and clients to gain first-hand appreciation of existing or future conditions through active engagement with prototypes.
• (^) Experience is a very dynamic, complex and subjective phenomenon. It depends upon the perception of multiple sensory qualities of a design, interpreted through filters relating to contextual factors.