HUMAN-COMPUTER THIRD DIX FINLAY INTERACTION EDITION ABOWD BEALE chapter 9 evaluation techniques
chapter 9 evaluation techniques
HUMAN-COMPUTER NTERACTION Evaluation Techniques Evaluation tests usability and functionality of system occurs in laboratory field and or in collaboration with users evaluates both design and implementation should be considered at all stages in the design life cycle
Evaluation Techniques • Evaluation – tests usability and functionality of system – occurs in laboratory, field and/or in collaboration with users – evaluates both design and implementation – should be considered at all stages in the design life cycle
HUMAN-COMPUTER NTERACTION Goals of evaluation assess extent of system functionality o assess effect of interface on user identify specific problems
Goals of Evaluation • assess extent of system functionality • assess effect of interface on user • identify specific problems
HUMAN-COMPUTER NTERACTION Evaluating Designs Cognitive Walkthrough Heuristic Evaluation Review-based evaluation
Evaluating Designs Cognitive Walkthrough Heuristic Evaluation Review-based evaluation
HUMAN-COMPUTER NTERACTION Cognitive Walkthrough Proposed by polson et al evaluates design on how well it supports user in learning task usually performed by expert in cognitive psychology expert walks though design to identify potential problems using psychological principles forms used to guide analysis
Cognitive Walkthrough Proposed by Polson et al. – evaluates design on how well it supports user in learning task – usually performed by expert in cognitive psychology – expert ‘walks though’ design to identify potential problems using psychological principles – forms used to guide analysis
HUMAN-COMPUTER NTERACTION Cognitive Walkthrough(ctd) For each task walkthrough considers what impact will interaction have on user? what cognitive processes are required? what learning problems may occur? Analysis focuses on goals and knowledge: does the design lead the user to generate the correct goals?
Cognitive Walkthrough (ctd) • For each task walkthrough considers – what impact will interaction have on user? – what cognitive processes are required? – what learning problems may occur? • Analysis focuses on goals and knowledge: does the design lead the user to generate the correct goals?
HUMAN-COMPUTER NTERACTION Heuristic Evaluation Proposed by nielsen and molich usability criteria(heuristics are identified design examined by experts to see if these are violated Example heuristics system behaviour is predictable system behaviour is consistent feedback is provided Heuristic evaluation debugs design
Heuristic Evaluation • Proposed by Nielsen and Molich. • usability criteria (heuristics) are identified • design examined by experts to see if these are violated • Example heuristics – system behaviour is predictable – system behaviour is consistent – feedback is provided • Heuristic evaluation `debugs' design
HUMAN-COMPUTER NTERACTION Review-based evaluation Results from the literature used to support or refute parts of design Care needed to ensure results are transferable to new design Model-based evaluation Cognitive models used to filter design options e.g. GOMS prediction of user performance Design rationale can also provide useful evaluation information
Review-based evaluation • Results from the literature used to support or refute parts of design. • Care needed to ensure results are transferable to new design. • Model-based evaluation • Cognitive models used to filter design options e.g. GOMS prediction of user performance. • Design rationale can also provide useful evaluation information
HUMAN-COMPUTER NTERACTION Evaluating through user Participation
Evaluating through user Participation
HUMAN-COMPUTER NTERACTION Laboratory studies · Advantages: specialist equipment available uninterrupted environment Disadvantages lack of context difficult to observe several users cooperating Appropriate if system location is dangerous or impractical for constrained single user systems to allow controlled manipulation of use
Laboratory studies • Advantages: – specialist equipment available – uninterrupted environment • Disadvantages: – lack of context – difficult to observe several users cooperating • Appropriate – if system location is dangerous or impractical for constrained single user systems to allow controlled manipulation of use
