INTERACTION D ESIGN
1 Analytical Evaluation: Inspections and Predictive
Models O VERVIEW
Involves real users
Usability Test: controlled environment
Field Study: natural environment
Does not involve real users.
Inspections: experience from experts
Several Kinds of Inspections in
E.g. code inspections for quality assurance.
In Interface Inspections
Experts use their knowledge of users &
technology to review software usability.
Expert critiques (crits) can be formal or
Heuristic evaluation is a review guided by
a set of heuristics.
Walkthroughs involve stepping through a
pre-planned scenario noting potential
problems. 3 H EURISTIC EVALUATION
Developed Jacob Nielsen in the early
Based on heuristics distilled from an
empirical analysis of 249 usability
These heuristics have been revised for
Heuristics being developed for mobile
devices, wearables, virtual worlds, etc.
Design guidelines form a basis for
developing heuristics. N IELSEN ’S H EURISTICS
Visibility of system status.
Match between system and real world.
(reflects quality of …?)
User control and freedom.
Consistency and standards.
Recognition rather than recall.
Flexibility and efficiency of use.
Aesthetic and minimalist design.
Help users recognize, diagnose, recover from errors.
Help and documentation. 5 H OW H EURISTIC EVALUATION IS
Training of evaluators (approx. 1 week)
Briefing session to tell experts what to do.
Evaluation period of 1-2 hours in which:
Each expert works separately;
Take one pass to get a feel for the product;
Take a second pass to focus on specific
Debriefing session in which experts work
together to prioritize problems.
6 H OW M ANY H EURISTICS? HOW M ANY
Not be too many (>10) to remember
Not be too few (<5) to be difficult to
Heuristic evaluation is referred to as
discount evaluation when many
evaluators are used
Between 3-5 evaluators has been found to be
the optimal (finds 75%-80% of the errors)
But this may vary - it depends on the nature of
the problem 7 NO .OF EVALUATORS& PROBLEMS
8 H EURISTICS : PROS AND C ONS
Few ethical & practical iss