chapter 11: an evaluation framework group 4: tony masi, sam esswein, brian rood, & chris troisi

Chapter 11: An Evaluation Framework

Group 4: Tony Masi, Sam Esswein, Brian Rood, & Chris Troisi

Introduction

Evaluation helps ensure that product meets the users’ needs

Recall HutchWorld & Olympic Messaging System (OMS) – chapter 10

What to evaluate? usability user experience

Chapter Goals

Key concepts & terms to discuss evaluation

Description of evaluation paradigms & techniques

Conceptual, practical, and ethical issues

DECIDE framework for evaluation

Evaluation Paradigms

Key terms- evaluation paradigms, user studies

4 core evaluation paradigms “Quick and dirt” evaluation Usability testing Field Studies Predictive Evaluation

Key Terms

User studies involve looking at how people behave in their natural environments, or in the laboratory, both with old technologies and with new ones.

Evaluation Paradigm is the set of beliefs which guide any type of evaluation

“Quick and Dirty” Quick & Dirty evaluation describes the

common practice in which designers informally get feedback from users or consultants to confirm that their ideas are in-line with users’ needs and are liked.

Quick & Dirty evaluations are done any time.

The emphasis is on fast input to the design process rather than carefully documented findings.

Usability testing Usability testing involves recording typical

users’ performance on typical tasks in controlled settings. As the users perform these tasks they are watched & recorded on video & their key presses are logged.

This data is used to calculate performance times, identify errors & help explain why the users did what they did.

User satisfaction questionnaires & interviews are used to elicit users’ opinions. Recall HutchWorld and OMS

Field Studies Field studies are done in natural settings The aim is to understand what users do

naturally and how technology impacts them.

In product design field studies can be used to:- identify opportunities for new technology- determine design requirements - decide how best to introduce new technology- evaluate technology in use.

Field Studies Two Approaches

Outsider – observing and recording what happens as an outsider looking in

Insider – participant in study that explores the details of what happens in a particular setting

Predictive Evaluation Experts apply their knowledge of typical

users, often guided by heuristics, to predict usability problems. Note: heuristics- design principles used in

practice Another approach involves theoretically

based models. A key feature of predictive evaluation is

that users need not be present Relatively quick & inexpensive

Key Aspects of each Evaluation Paradigm Table 11.1 – page 344 role of users who controls the process & relationship

during evaluation location when is it most useful to evaluate type of data collected & how it is analyzed how findings are fed back to the design

process philosophy that underlies these

paradigms

Evaluation Techniques Observing users Asking users their opinions Asking experts their opinions Testing users’ performance Modeling users’ task performance

to predict the efficacy of a user interface

Observing Users Techniques

notes audio video interaction log

Asking users their opinions Questions like:

what do you think about the product? does it do what you want? do you like it? does the aesthetic design appeal to

you? did you encounter problems? would you use it again?

Asking experts their opinions Use heuristics to step through

tasks Typically use role-playing to

identify problems It is inexpensive and quick to ask

experts rather than perform laboratory and field evaluations

User Testing Recall HutchWorld example Usually conducted in a controlled

environment Users perform well-defined tasks Data can be collected and

statistically analyzed

Modeling users’ task performance

Model human-computer interaction to predict the efficiency and problems in the design

This is successful for systems with limited functionality

Table 11.2 - page 347

DECIDE: framework Determine the goals the evaluation

addresses. Explore the specific questions to be

answered. Choose the evaluation paradigm and

techniques to answer the questions. Identify the practical issues. Decide how to deal with the ethical

issues. Evaluate, interpret and present the data.

Determining the Goals What are the goals of the evaluation? Who wants it and why? Goals influence the paradigm for the study. Some examples of goals:

Check that evaluators have understood user needs

Check to ensure that the final interface is consistent.

Investigate how technology affects working practices.

Improve the usability of an existing product .

Explore the Questions All evaluations need goals & questions to

guide them so time is not wasted on ill-defined studies.

For example, the goal of finding out why many customers prefer to purchase paper airline tickets rather than e-tickets can be broken down into sub-questions:- What are customers’ attitudes to these new tickets? - Are they concerned about security?- Is the interface for obtaining them poor?

Choose Evaluation Paradigm and Techniques

Evaluation Paradigms determine which type of techniques will be used.

Trade-Offs

Combinations of Techniques -HutchWorld

Identifying Practical Issues

For example, how to:

select users stay on budget staying on schedule evaluators select equipment

Decide on Ethical Issues Consideration for peoples rights. Develop an informed consent form Participants have a right to:

- know the goals of the study- what will happen to the findings- privacy of personal information- not to be quoted without their agreement - leave when they wish

“do unto others only what you would not mind being done to you”

Evaluate, Interpret, and Present Data

Reliability Validity Biases Scope Ecological Validity

Pilot Studies Pilot Study is a small trial run of the

main study. Pilot studies are always useful for

testing plans for an evaluation, before launching the main study

Often evaluators run several pilot studies.