Information Systems Analysis and Design csc3402001 Marilyn Mantei and John MylopoulosInterface Design -- 1XXI. User Interface DesignXXI. User Interface DesignWhat is Human-Computer Interaction?Affordances, Mappings, Mental Models,Feedback, Forcing Functions, LearningHow to Design InterfacesUser Dialogue DesignInputs and OutputsInformation Systems Analysis and Design csc3402001 Marilyn Mantei and John MylopoulosInterface Design -- 2HCI = Human-ComputerHCI = Human-ComputerInteractionInteractionInformation Systems Analysis and Design csc3402001 Marilyn Mantei and John MylopoulosInterface Design -- 3Why Should a Systems AnalystWhy Should a Systems AnalystKnow HCI?Know HCI? 40-60% of today’s software consists of user interfaces. Such interfaces support high interactivity with the user,much end-user programming User interactivity is only going to get more complex: 3Dgraphics and virtual reality, augmented reality activities…. Many usability problems due to a bad interface design:Users sabotage systems they don’t understand;Users make more errors when dealing with systemsthat are difficult to use. A well-designed user interface can reduce coding costs,interface problems, life-threatening errors; can also leadto increased sales, …more...Information Systems Analysis and Design csc3402001 Marilyn Mantei and John MylopoulosInterface Design -- 4Increased ProductivityIncreased Productivity20 usersX230 daysX100 screens per dayX10 sec per screen (savings)=1278 hours or 32 weeksInformation Systems Analysis and Design csc3402001 Marilyn Mantei and John MylopoulosInterface Design -- 5Reduced Training CostsReduced Training Costs20 employeesX2 systems/applications per yearX2 1/2 days per application (saved)= 100 days or 20 weeks of savings Training and support often more costlyTraining and support often more costly than hardware and softwarethan hardware and softwareInformation Systems Analysis and Design csc3402001 Marilyn Mantei and John MylopoulosInterface Design -- 6Preventable User ErrorsPreventable User Errors500 usersX 20 errors per yearX15 minutes per error= 2500 hours lost or 63 weeksInformation Systems Analysis and Design csc3402001 Marilyn Mantei and John MylopoulosInterface Design -- 7Increased ProductivityIncreased Productivity500 menu selections per dayX2 sec per selection (saved)X230 days per year=320 hours or 8 weeksFor a $100K person-year cost, saved timeFor a $100K person-year cost, saved timetranslates to $15,000translates to $15,000Information Systems Analysis and Design csc3402001 Marilyn Mantei and John MylopoulosInterface Design -- 8Serious Life-Threatening ErrorsSerious Life-Threatening Errors Analysis of transcript of 911 call announcing bombin Centennial Park at the Atlanta Olympicsindicated that 20’ were needed to call dispatchersDispatch system required an address; operatorscould not find anyone who knew address;Bomb was set to go off 30 minutes after call. Airline crashed into a mountainside in Colombia in1996, killing all aboardPilot typed in “R” rather than full name of airport;Guidance system selected the first airport in thelist beginning with “R” -- which was the wrongairport;Information Systems Analysis and Design csc3402001 Marilyn Mantei and John MylopoulosInterface Design -- 9User Interface EconomicsUser Interface Economics Good user interfaces sell systems!Windows is a copy of the Macintosh interface;The Mac interface is a copy of Bravo - developedby user interface researchers at Xerox PARC. User interface capabilities and awareness help getcontracts. Poor user interfaces can cripple a system that isoutstanding in all other respects. Poor computer-driven interfaces placed in mostmechanical products we knowWho can set the clock on their VCR?Who can use photocopy, fax, candy, bankmachine, cash register, telephone…;Information Systems Analysis and Design csc3402001 Marilyn Mantei and John MylopoulosInterface Design -- 10Why Are User Interfaces Poor?Why Are User Interfaces Poor? Inadequate training of people developing interfaces. Diverse knowledge required to design interfaces. Rapid technological advances. Poor management - programmers do not talk to userdesign teams and vice versa. User Interface specialists rarely involved. The "bricklayers" (programmers) are left to design theuser interface, by default.““Ignorance by software engineers of usabilityIgnorance by software engineers of usabilityand how to measure it is roughly equivalent toand how to measure it is roughly equivalent toan electronics engineer not knowingan electronics engineer not knowingwhat volts and watts are and how to measurewhat volts and watts are and how to measurethem."them."Information Systems Analysis and Design csc3402001 Marilyn Mantei and John MylopoulosInterface Design -- 11WhatWhat’’s Wrong with this Interface?s Wrong with this Interface?Design ofDesign ofUserUserInterfaceInterfaceforforCAVECATCAVECATMediaMediaSpaceSpaceInformation Systems Analysis and Design csc3402001 Marilyn Mantei and John MylopoulosInterface Design -- 12Why is thisWhy is thisDesignDesignBetter?Better?Design of UserDesign of UserInterface forInterface forTelepresenceTelepresenceMedia SpaceMedia SpaceInformation Systems Analysis and Design csc3402001 Marilyn Mantei and John MylopoulosInterface Design -- 13Some Basic Human CharacteristicsSome Basic Human Characteristics Humans like problem solving, for solvable problems! Humans are always learning, but learning is hard! Humans use prior learning to support new learning. Users don’t read manuals, work by copying and asking. Users are always building models of their world. ImplicationsBuild interfaces that allow people to learn by usinglearn by usingthe interface;Build interfaces that suggest correct models;Build interfaces that rely on prior learning.Information Systems Analysis and Design csc3402001 Marilyn Mantei and John MylopoulosInterface Design -- 14More Human Characteristics Users don’t mind if something doesn’t make sense -- they build their own model to make it make sense.
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