Evaluating Interfaces with Users: Quantitative Methods
This section introduces quantitative methods for evaluating interfaces with users,
concentrating on experimental design, controlled experimentation, and simple statistics.
An assignment on quantitative
evaluation gives students practise in a controlled experiment.
Overheads
Topics Covered
- Quantitative evaluation methods
- User performance data collection
- Controlled experiments
- The experimental method
- Planning an experiment
- The value of statistics
- Example: T-test
- Significance levels, types of error
- Other statistical tests
- (Optional) Analysis of variance
- terminology
- factorial design
- case study
Readings from Baecker Grudin Buxton and Greenberg
- Chapter 2: Design and Evaluation, p.73-91. The sections directly relevant to
quantitive evaluation are c) Controlled experiments.
- Methodology Matters: Doing Research in the Behavioural and Social Sciences,
p.152-169, covers many fundamental issues in empirical research methodologies.
Videos
Touch Typing with a Stylus, shows a pen-based character input system. This is presented
as a radically different alternative to the screen-based keyboards evaluated in the
example assignment.
- Touch Typing with a Stylus, by Xerox (1993, SGVR 88)
In-Class Teaching tips
In-class quantitative controlled experiment. In a short HCI course I once
offered, there was no time for students to do the related assignment. Instead, I run a
subject in class through a controlled experiment to give people an idea of what they have
to do (their task was mouse-typing on two soft keyboards with different layouts, specified
in the assignment 1). Students then run each other as subjects out of class (since the
software is set up for them, it takes them only 15 minutes). They hand in the data, and we
analyze and interpret it in a later class.
Major sources used to prepare lecture material
- For quantitative evaluation, the reading Methodology matters provides good
general background. Other sources I used include general psychology statistics books, and
chapters in HCI textbooks dealing with controlled experiments (e.g., Chapter 11.5.1 in Human
Computer Interaction by Dix, Finlay, Abowd and Beale).
- The research planning chart came from an old CHI tutorial, but I've since lost track of
who actually created it.
Last updated September 1997, by Saul Greenberg