1. how can weimprove the usabilityof a design? 1lecture 03 |
219 digital concepts | structurejoe natoli | givegoodux.com
2. 80/20 rulejoe natoli | givegoodux.com
3. 80/20 rule 3 80% of a products usage involves 20% of its
features 80% of a towns trafc is on 20% of its roads 80% of
progress comes from 20% of the effort 80% of errors are caused by
20% of the componentsjoe natoli | givegoodux.com
4. 80/20 rule 4 3 all elements in a design are not equal use
the 80/20 rule to assess the value of elements, target areas of
redesign and optimization, and focus resources if the critical 20%
of a products features are used 80 percent of the time, design
should focus primarily on those features non-critical functions
that are part of the less-important 80% should be minimized or
removed altogether from the designjoe natoli | givegoodux.com
5. accessibilityjoe natoli | givegoodux.com
6. accessibility 6 3 things should be designed to be usable by
as many people as possible often focused on helping people with
disabilities increasingly clear that many required accommodations
can be designed to benet everyone also known as barrier-free design
and related to universal design and inclusive designjoe natoli |
givegoodux.com
7. accessibility 7 3 perceptibility means everyone can perceive
the design, regardless of sensory abilities operability means
everyone can use the design, regardless of physical abilities
simplicity means everyone can easily understand and use the design,
regardless of experience, literacy, or concentration level
forgiveness means designs minimize the occurrence and consequences
of errorsjoe natoli | givegoodux.com
9. aesthetic-usability 9 aesthetic designs are perceived as
easier to use than less-aesthetic designs its common for people to
name and develop feelings toward designs that have fostered
positive attitudes (e.g., naming a car) personal, positive
relationships with a design evoke affection, loyalty, and
patienceall signicant factors in long-term success these positive
relationships also make people much more tolerant of errorsjoe
natoli | givegoodux.com
10. conrmationjoe natoli | givegoodux.com
11. conrmation 11 veries that an action or input is intentional
and correct before its performed conrmations slow task performance
reserve for use with critical or irreversible operations only allow
less critical conrmations to be disabled after an initial
conrmationjoe natoli | givegoodux.com
12. constraintsjoe natoli | givegoodux.com
13. constraints 13 constraints limit possible actions for
example, hiding unavailable software controls constrains the
options that can be selected simplies usability and minimizes error
can reduce the sensitivity of controls minimizes unintentional
inputs prevents or slows dangerous actionsjoe natoli |
givegoodux.com
14. physical constraints 14 paths convert applied forces into
linear or curvilinear motion using channels or grooves (e.g. scroll
bar in user interfaces) axes convert applied forces into rotary
motion, providing a control surface of innite length in a small
space (e.g. a trackpad) barriers absorb or deect applied forces
stopping, slowing, or redirecting forces around the barrier (e.g.
boundaries of a mobile phone screen)joe natoli |
givegoodux.com
15. psychological constraints 15 symbols inuence behavior by
communicating meaning through visuals and/or language (e.g. text
& icon of a warning sign) conventions inuence behavior based on
learned traditions, practices and mental models (e.g. red means
stop, green means go) mappings inuence behavior based on perceived
relationships between elements (e.g. light switch position)joe
natoli | givegoodux.com
16. controljoe natoli | givegoodux.com
17. control 17 level of control provided by a design should be
related to the prociency and experience levels of the people using
it beginners do best with reduced amount of control experts do best
with greater amount of control interactive design can accommodate
these varying needs by offering multiple ways to perform a taskjoe
natoli | givegoodux.com
18. cost - benetjoe natoli | givegoodux.com
19. cost-benet 19 an activity will be pursued only if its
benets are equal to or greater than the costs determines design
quality from a user perspective: if costs associated with
interaction outweigh the benets, the design is poor if the benets
outweigh the costs, the design is goodjoe natoli |
givegoodux.com
20. cost-benet 20 how much reading is too much to get the point
of a message? how many steps are too many to set the time and date
on your camera? how long is too long for a person to wait for a web
page to download? it depends on the benets of the interaction
design features or elements that excite designers are often never
used or even noticed by peoplejoe natoli | givegoodux.com
21. entry pointjoe natoli | givegoodux.com
22. entry point 22 we do judge books by their covers, apps or
sites by their rst pages ever click on a URL only to see a splash
screen,followed by several pop-up windows with ads, followed by a
slow-loading page? all just to enter a site that didnt have the
information you were looking for? these errors in entry point
design annoy visitors who make it through, or deter visitors
altogetherjoe natoli | givegoodux.com
23. errorsjoe natoli | givegoodux.com
24. errors 24 two kinds of errors: slips are the result of
automatic, unconscious processes, and frequently result from a
change of routine or an interruption of an action. (e.g. you forget
your place in a procedure when interrupted by a phone call)
minimize by providing clear feedback: consequences and corrective
actions position controls to prevent accidental activation of
functions that may have detrimental consequencesjoe natoli |
givegoodux.com
25. errors 25 mistakes are conscious, sometimes referred to as
errors of intention or errors of planning, and occur when an
intention is inappropriate. (e.g. nurse interprets an alarm
incorrectly and then administers the wrong medicine) minimize by
increasing situational awareness and reducing noise make key
indicators and controls visible within one eyespan when possible
provide just enough feedback to accomplish warnings and other
functions, but no more.joe natoli | givegoodux.com
27. iconic representation 27 similar iconic images that are
visually analogous to an action, object, or concept most effective
at representing simple actions, objects, or concepts, and less
effective when the complexity increasesjoe natoli |
givegoodux.com
28. iconic representation 28 example images of things that
exemplify or are commonly associated with an action, object, or
concept particularly effective at representing complex actions,
objects, or conceptsjoe natoli | givegoodux.com
29. iconic representation 29 symbolic iconic images that
represent an action, object, or concept at a higher level of
abstraction effective when actions, objects, or concepts involve
well-established and easily recognizable objectsjoe natoli |
givegoodux.com
30. iconic representation 30 arbitrary iconic images that bear
little or no relationship to the action, object, or conceptthe
relationship has to be learned should only be used when developing
cross-cultural or industry standards that will be used for long
periods of time this gives people sufcient exposure to an icon to
make it an effective communication devicejoe natoli |
givegoodux.com
31. performance loadjoe natoli | givegoodux.com
32. performance load 32 degree of mental and physical activity
required to achieve a goal if the performance load is high,
performance time and errors increase, and the probability of
successful accomplishment decreases if the performance load is low,
performance time and errors decrease, and the probability of
successful accomplishment increases two types of performance loads:
cognitive and kinematicjoe natoli | givegoodux.com
33. performance load 33 cognitive load amount of mental
activityperception, memory, problem solvingrequired to accomplish a
goal e.g. remembering commands vs. graphical UI strategies for
reducing cognitive load: minimizing visual noise chunking
information using memory aids automating computation- and/or
memory-intensive tasks.joe natoli | givegoodux.com
34. performance load 34 kinematic load degree of physical
activitynumber of steps or movements, or amount of forcerequired to
accomplish a goal e.g. the telegraph communicated letters one at a
time through a series of taps on a mechanical armature. strategies
for reducing kinematic load: reducing steps required to complete
tasks minimizing range of motion and travel distances automating
repetitive tasksjoe natoli | givegoodux.com
35. personasjoe natoli | givegoodux.com
36. personas 36 its better to perfectly meet the needs of the
critical few than to poorly meet the needs of many personas involve
the creation of proles for a small number of archetypal users, each
prole representing a composite of a subpopulation of users
information for the proles comes from user and stakeholder
interviews, reviews of market research and customer feedback, and
statistics on product usejoe natoli | givegoodux.com
37. recognition over recalljoe natoli | givegoodux.com
38. recognition over recall 38 people are better at recognizing
things theyve previously experienced than recalling those things
from memory recognition tasks provide cues that facilitate
searching through memory e.g. multiple-choice vs. short-answer
question recognition memory is built through exposure its something
that has been experienced before e.g. sight, sound, smell, touch
minimize the need to recall information from memory whenever
possiblejoe natoli | givegoodux.com
39. wayndingjoe natoli | givegoodux.com
40. waynding 40 whether navigating a college campus, the wilds
of a forest, or a website, waynding involves the same four stages:
orientation route decision route monitoring destination
recognitionjoe natoli | givegoodux.com
41. waynding 41 successful waynding in UI design answers the
following user questions: where am I? how did I get here? where
else can I go? how will I know when Im there?joe natoli |
givegoodux.com
42. assignment For next weeks class, rene your interface
concept based on the feedback and suggestions you received in
critique last week. How can you improve what you have now? We will
have a critique at the beginning of class next week.joe natoli |
givegoodux.com