31-05-2012, 03:58 PM
Empirical Research in HCI:What? Why? How?
Empirical Research in HCI.ppt (Size: 505.5 KB / Downloads: 32)
Observe and Measure
Observations are gathered…
Manually (human observers)
Automatically (computers, software, sensors, etc.)
A measurement is a recorded observation
When you cannot measure, your knowledge is of a meager and unsatisfactory kind.
Ratio Measurements
Preferred scale of measurement
With ratio measurements summaries and comparisons are strengthened
Report “counts” as ratios where possible
Example – a 10-word phrase was entered in 30 seconds
Bad: t = 30 seconds
Good: Entry rate = 10 / 0.5 = 20 wpm
Example – two errors were committed while entering a 10-word (50 character) phrase
Bad: n = 2 errors were comitted
Good: Error rate was 2 / 50 = 0.04 = 4%
Research Questions
Why do we conduct empirical research?
Simply…
To answer (or raise!) questions about a new or existing UI design or interaction technique!
Questions include…
Is it viable?
Is it as good as or better than current practice?
Which of several design alternatives is best?
What are its performance limits and capabilities?
What are its strengths and weaknesses?
Does it work well for novices, for experts?
How much practice is required to become proficient?
Test Environment Example
Scenario…
You wish to compare two input devices for remote pointing (e.g., at a projection screen)
External validity is improved if the test environment mimics expected usage
Test environment should probably…
Use a projection screen (not a CRT)
Position participants at a significant distance from screen (rather than close up)
Have participants stand (rather than sit)
Include an audience!
But… is internal validity compromised?