Overview of the rest of the semester Building on Assignment 1 Using iterative prototyping

Important announcement!

Next week our lecture will be in a new secret location… Piazza message coming.

Looking ahead… The rest of the semester

Lab sequence Week 8 – Heuristic Evaluation in class of both prototypes – Inter-group expertise provided Week 9 – Technical work + prototype refinement – Drawing on lessons from Week 8 Week 10 - Think-aloud studies in class – Inter-group, with different people from last week Week 11 – Write up the above studies and discuss in class – Monday class special Week 12 – Deliver presentations and demos – Monday class special Week 13 – Revision for the exam

Stretch task - backend Benefits of a backend – Abstraction…. – Can create greater flexibility and cover more tasks Disadvantages – Influence of the difficulties of implementation on design – Programming well!

Feedback on presentations (+reports) Role of presentation – Verbal + visual + other media – Immediate Role of reports – Written expression – Visual and text, layout organisation – Finalised form only

Assignment 2 Second presentation – Design – Usability Demo

GOMS and keystroke predictive methods for expert users When (fine-grained) speed matters

Overview GOMS and keystroke analyses Keystroke analysis Detailed timing Big picture Predictive methods Benefits Disadvantages Adapting GOMS to newer devices (>1 million Google matches)‏ 10

Learning Objectives Describe the uses of GOMS Describe the processes for conducting GOMS analyses Describe advantages and limitations Ability to perform a GOMS study on conventional WIMP interfaces Justify the use of GOMS in the overall testing of a system 11

GOMS Goal Operations - keystrokes, clicks Methods - sets of operations Selection rules - decide between methods For expert users For assessing speed of use 12

Who: Target users and their tasks Experts – In using this application – Trained in domain – And in the tool Speed of task completion Focus on performance Relevant to the interfaces for the small core of tools that people use extensively – Word processors – Domain specific eg teacher’s software for marks For cases where people have time to automate their interaction – eg using a word processor to write a report, the focus needs to be the report writing, not the fine-grained actions to type words, revise the document etc

Who: expertise needed to conduct a GOMS analysis effectively? GOMS requires expert evaluators – For use of the method – For selection of appropriate tasks to consider Highly specialised – to do well, need to be very skilled – Very tedious, especially by hand – Real use uses automated tools (with their learning curve) However, keystroke analysis can be useful for designers more generally.. Useful for your toolkit

What: usability aspects does it assess? Only for performance speed (Not all those other important aspects….learnability, error recovery, satisfaction…)

How: do you need users? NO! Predictive no users needed …. low cost

When: to do keystroke or GOMS analysis During early design Potentially also when revisiting the design, in Agile approaches When considering what interaction options to implement

Role and Time in design process Designing the interaction methods – eg whether to have multiple ways to do an action Deciding what interaction methods to implement – eg keyboard shortcuts

Class activity Which of the following are appropriate interfaces for using GOMS in the design of interaction – Designing a new element of a word processor (like Word) – Spreadsheet (A: Yes – a core productivity tool for a very wide user population) – Web site for university students to enrol in their subjects each year Specialised software for bank- tellers to handle customer queries on accounts – CUSP – E-textbook

Class activity – comparing methods for pragmatic issues MethodRequires users? Quite easy for inexpert UE-ers? Relevant where UI is for novice, intermittent users? Relevant where UI is for expert users? Think Aloud Y/N/Part* Heuristic Evaluation Cognitive Walkthrough GOMS

Class activity – purpose MethodAssess learnability? Assess efficiency? Assess memorability? Assess errors? Assess satisfaction ? Think Aloud Heuristic Evaluation Cognitive Walkthrou gh GOMS