§9- Heuristic Evaluation & Cognitive Walkthrough Flashcards
Bits of waterfall model relevant to HE and CW?
- evaluating and refining requirements
Recap issues about usability
- Ease of learning
- Recall: remember how to use next time
3: Productivity: execution time
4: Minimal error rates: feedback on error, recovery - Satisfaction: user confident of success
Benefits of ``discount usability testing’’ compared to formal usability testing
- fewer resources and time than formal usability testing
Three examples of discount usability testing
- lofi prototyping
- heuristic eval (heuristics, severities, process)
- cognitive walkthrough
Purpose of HE + high level overview
- find usability problems in a user interface
2. 5 evaluators is optimal, check compliance with usability heuristics, compile problems, inform redesign
List the ten usability heuristics
- visibility of system status
- match sys real wrld
- user control, freedom
- consistency, standards
- error prevention
- recognition rather than recall
- flex/efficient use
- aesthetic, minimalist design
- help users recognise and recover from errors
- help, documentation
+ skills
+ privacy,
+ pleasurable interaction/respectful
Outline the steps needed to perform heuristic evaluation
- pre eval training: train assessors about problem domain, scenarios
- evaluate: go through UI according to scenarios, at least twice
- collate
- rate severity
- feedback into next iteration of design
issues related to severity ratings + meanings
- determined from frequency, persistence, impact of problem
- calculated after evaluations are complete
- decide between more assessment and/or redesign
- 0: don’t agree that it is a problem
- 1: cosmetic
2: minor usability problem
3: major usability problem + important to fix
4: usability catastrophe + imperative to fix
H1 Visibility of System Status
Keep users informed about what is going on through appropriate feedback within reasonable time
- longer delays – progress bars
H2 Match to real world
Speak the users’ language
Follow real world conventions
e.g. itunes, photoshop tools
H3 user control and freedom
Clearly marked “exits” for mistaken choices undo/ redo
Do not force down fixed paths
e.g home button
H4 consistency and standards
Consistency within and between applications
- similar objects/terminology for similar actions
same primary menu options for Word, Excel, PowerPoint
H5 error prevention
What is better than good error messages is a careful design, which prevents a problem from occurring in the first place
- e.g. PIN entry fields, google autocomplete
H6 recognition rather than recall
Minimize user’s memory load
Make objects, actions, options, and directions visible or
easily retrievable
- e.g. adobe photoshop filter thumbnails
H7 flexibility for efficient use
accelerators – keyboard shortcuts,
allow tailoring – macros
Support frequent tasks and tasks
with high cognitive load – copy paste
HE problems exam question points
- which heuristics are violated and why
- what is the severity rating
- why - what is the effect on the user
- how would you fix the problem
H8 aesthetic and minimalist design
- Draw user to focus on main subject at hand
- categorise repetitive information into relevant sections
- split long menus up
- toolbars with icons/tooltips
H9 help users recognise and recover from errors
- help users recognise when an error has occurred
- error messages in plain language to precisely indicate the problem
- constructively suggest a solution
H10 help and documentation
- should be easy to search
- focused on user’s task
- list of concrete steps to carry out
- not too long
Drawbacks of HE
- not task focussed
- may be too high level - not using actual users
- not rigorous
CW-why
- question assumptions about what users will be thinking
- identify obscure/missing controls
- find places that have inadequate feedback
- suggest difficulties users may have with labels or prompts
- identify problems users have on first use without training
- not useful for evaluating usability over time (learning, speed of transition from beginner to intermediate)
- assesses learnability of UI
- identifies specific problems rather than general problems
- no need for users to get involved
Preparation for CW
- description of prototype
- task description
- list of actions
- idea of users, experience they bring
5 steps of cognitive walkthrough
- define inputs
- get analysts
- step through action sequences for each task
- record important information
- revise UI
Step 1 : define inputs
- who are the users,
- what are the tasks
- what are the action sequences for the tasks
- have prototype/description of the interface ready
Step 2: get analysts
- don’t need actual users
- could imagine behaviour of entire class of users.
- bear in mind cognitive limitations when performing walkthrough
Step 3: step through actions
- will users know what to do?
- will users see how to do it?
- will users understand from the feedback whether their actions are correct or not?
Step 4: record important information
- user knowledge just before and after each action
- assumptions about users
- side issues, design changes
- credible success or failure story – why would a user select or not select the correct action
Step 5: revise UI
- if user failed to select right action: eliminate, add prompt, change to make more visible
- user does not know that correct action is available: make action more obvious
- user does not know which action is correct: label controls based on user knowledge, check whether sequence of actions is natural/or seems awkward
- if user can’t tell things are going OK - give user feedback, say what happened in response to their action
Problems found by CW
- severe problems with usability
- content related problems (since requires actual use of the interface to solve a goal)
- scope – more specific (thereby arguably superficial) than general
Issues with CW
- cannot evaluate all tasks, users may have different action sequences
- each task is evaluated separately; what about cross task interactions
- task free user centred method needed to catch problems that CW may have missed e.g. HE
