End goals. Derived from. End goals Experience goals Life goals. End goals Experience goals

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1 Derived from product goals goals problems environment End goals Preserves transaction slips after ATM use Saves incoming s Shuts off past pages by a rubber band Uses tattered bag to carry lot of money 1 2 End goals Experience goals Not take too much trouble Not look foolish Feel competent End goals Experience goals Life goals Be great Earn lots of money 3 4

2 5 Expressed needs Latent needs Drudgery Lack of information Errors, delays, confusions Failures of current systems 6 Physical Snow, sun or sandstorm Power failures Excellent fiber network Cultural Need for security Personal contact Triggers for action Start of a semester Rush order comes in Set goals before starting the design goals may be qualitative and quantitative Qualitative Useful in guiding initial design Drawn from user profiles and deep understanding of users work patterns 7 8

3 Qualitative Quantitative Useful in guiding initial design Drawn from user profiles and deep understanding of users work patterns Support work in a high-interrupt, distracting environment Enable tourists new to city to look up information Recognize a user irrespective of number of accounts Facilitate group operations Provide consistency across operations Relative goals Improve speed of use by 25% Reduce errors by 30% Absolute goals Minimum acceptable level for each goal for release of the product More detailed goals (unacceptable, minimum, target, exceeds target) 9 10 Categories of Learnability Learnability Ease of use Speed of use Error-free use Retention over time Subjective satisfaction Learnability goals are the most fundamental usability goals 11 12

4 Learnability Learnability 13 Novice users First time usability of the product Tourists should be able to find out the number of the bus they need to take. First year students should be able to register without help. Advanced beginners / competent performers Ease to learn more features Ease to improve conceptual models Regular customers should learn to use the one click feature. Daily customers should be able to order vegetables on their cell phones. 14 First version All users start out being novices Have no knowledge of the product Recognize terms used in the interface. Subsequent versions s will transfer existing knowledge s will have to learn the differences Be 100% backward compatible with these tasks s should notice the new wizard. Example Questions Ease of Use How quickly can a novice user start using the product? How quickly can a novice user become an advanced beginner and an advanced beginner become a competent performer? How much of training and practice is necessary? Is the user encouraged to explore the product? Define tasks a given user must be able to do All advanced beginners should be able to find and replace text. Define a preferred method of doing things All competent performers should be able to do a find operation on multiple documents with one command rather than opening each file separately. Avoidable tasks s need not write anything on the deposit envelope

5 Example Questions Speed of Use How many users can perform the tasks that they are supposed to? How many tasks do users need to do that are avoidable? How easy is it for a group of users to work together? How easily does the product fit in the users current conceptual model? Time taken It should take a farmer less than five minutes to identify a transporter. Number of steps A novice user should be able to deposit cash at the ATM in 3 steps. Regular commuters should be able to tell time to the next bus without clicking. Same as ease of use? Example Questions Error free Use How long does it take for the user to carry out benchmark set of tasks? How many steps are involved in a routine task? How long does it take for users to recover from errors? Error An action of the user that does not accomplish the desired goal Error Rate of a product Number of errors made by users while performing benchmark tasks Percentage of users who make an error while doing a task Severity of Errors The more difficult it is to recover from the error, more sever it is 19 20

6 Error free Use Example Questions 21 Limits for error rate of the product Should be able to identify himself without errors Limits for severity of the errors (catastrophic, major, minor) It should be impossible for transporters to loose data. Prevent users from entering more amount than they can withdraw. Ability of users to recognize errors Error messages should not be confused with other messages. Ability of users to recover from errors 22 How many and what kind of errors are made by users to carry out benchmark tasks? How many errors do users make repeatedly? How long does it take for the users to identify the error condition? How forgiving is the interface? What percentage of errors can users recover from? How many users can identify the cause of the error and the method of recovering from errors? How long does it take for users to recover from errors? Retention Over Time Retention Over Time Most advanced beginners are intermittent users Don t have to learn the system from scratch They just need to remember how to use the system based on their previous experience Parts of the interface that are used intermittently Installation programs Backup Restore Retention is rarely tested A product that is easy to learn is considered to be easy to retain Define goals are for guiding design 23 24

7 Example Questions Subjective Satisfaction How much of the interface can a user recall after pre-determined amount of time (hours, days, months, years)? With how much effort and time can a user relearn what he has forgotten? Expectations of pleasantness Derived from life goals and experience goals of users Significantly influence the desirability Important for non-work products Home computing, games, fiction Important for niche markets Hasselblad for photographers Apple Mac for designers Manual blood pressure meter for doctors Example Questions How much did the users enjoy using the product? Is it value for money or is it hassle free trip? What are the cultural issues that matter? How do users rate the product over competition? Learnability Ease of use Error-free use Speed of use Retention over time Subjective satisfaction 27 28

8 Goal Driven Design You Can t Meet All drive design Help speed up design process Make design activity tangible Help evaluate design Railway signals, ATC, operation theatre, water supply Reliability, error free use, long training Set goals before design!!! You Can t Meet All You Can t Meet All Banks, railway reservation, inventory Speed of use, minimal training, operator fatigue and burnout Home, office, public places Office products, ATMs, cell phones Some tasks with zero learning, encourage self learning and exploration, support wide range of users (A/NB/CP), subjective satisfaction 31 32

9 You Can t Meet All You Can t Meet All Home, office, public places Exploratory and creative Architecture, graphic design, product design, audio studio, GIS / GPS / MIS Ease of use, some training, encourage self learning and exploration Home, office, public places Exploratory and creative Cooperative work Chat, mailing lists, DLP Some tasks with zero learning, ease of use, encourage self learning and exploration, support wide range of users (A/NB/CP), subjective satisfaction You Can t Meet All Assignment 4 Home, office, public places Exploratory and creative Cooperative work Micro interface Hardware, Devnagari keyboard, new paradigm Demonstrate new concept, attract early adaptors, zero learnability, ease of use Identify an interactive product that you think is badly designed For two examples, analyze how the product fails and for which category of users (N/AB/CP/EP) Provide photographs / screen shots if necessary Suggest usability goals in a redesign task Submission February 9 (.ppt OK?) 35 36