pucd

Principles of User-Centered Design : Principles of User-Centered Design CSCI 4800/6800 Feb. 1, 2006


What is design? : What is design? Finding the right components of a physical structure A goal-directed problem-solving activity Simulating what we want to make or do before we make or do it – as many times as may be necessary to feel confident in the final result Engineering design: “the use of scientific principles, technical information and imagination in the definiton of a mechanical structure, machine or system to perform pre-specified functions with the maximum efficiency and economy.


Approaches : Approaches Formal specifications Custom crafted / creative


User-Centered Design : User-Centered Design Principles Make user issues central in the design process Carry out early testing and evaluation with users Design iteratively


Methods for UCD : Methods for UCD Soft Systems Methodology (SSM) Open Systems Task Analysis (OSTA) Multiview Star Life Cycle


Soft Systems Methodology : Soft Systems Methodology Focuses on planning Approach developed by Checkland, Schloes ’81, ’91 Emphasis : understand the problem and its situation


SSM : SSM


Stages in SSM : Stages in SSM Stages 1 and 2 – obtain “rich expression” of the problem: meetings with stakeholders Stage 3 – obtain precise definition of the system Stage 4 – produce conceptual models: abstract representation, “root definition”


SSM, “root definition” : SSM, “root definition” C - Clients (people who will benefit/suffer) A - Actors (who is involved with system) T - Transformation (purpose) W - Weltanschauung/World View (perspective from which root definition is formulated) O - Owners (who has commissioned system) E - Environment


SSM : SSM Stage 5 – compare “root definition” of stage 4 with “rich expression” of stage 2; iterate until gaps are filled Stage 6 – identify changes Stage 7 – recommend an action


SSM : SSM Benefits for HCI engineering: Identifies people, constraints, view of system Develops conceptual models


Cooperative Design : Cooperative Design Participative design – users participate in design process Sociotechnical design – considers both social and technical alternatives/solutions to/ aspects of problems OSTA – Open Systems Task Analysis (Eason, Harker ’89)


OSTA : OSTA


OSTA : OSTA Specified together: Technical requirements System structure, functionality Social system requirements Usability, acceptability Goal: Provide method for understanding what occurs when computer system is introduced into a working environment


OSTA – Systems Analysis (top) : OSTA – Systems Analysis (top) Primary task stated (goals of group of workers identified) Task inputs identified - usually come from outside the system - character of inputs may vary & affect way system behaves External environment - including physical environment, economic, political conditions, demand for task output Transformation processes described typically - object/action flowchart of objects to be transformed & actions neccessary to transform them with annotations


OSTA – technical and social : OSTA – technical and social 5. Social system analyzed Roles of people in relation to one another Characteristics & qualities of users of new system Technical system analyzed - how will new system be integrated with others systems & what remains of the old system? Performance satisfaction – for social system under new technical systems Requirements for new technical system, based on the task analysis Functionality, usability, acceptability


Problems: : Problems: Need expert to guide the design process Ability to integrate with other design processes/methods Need “right” organizational and political climate Cost-effective???


Multiview : Multiview Combines sociotechnical and soft-systems approaches Stage 1: create PTM (primary task model) – similar to “root def” Stage 2: conceptual modeling of info flows/ structure, produce FM (functional model), ER model, dataflow models Stage 3: design people tasks (PT), role sets (RS), and computer task requirements (CTR) Stage 4: design the HCI Stage 5: technical design


Multiview : Multiview


Multiview : Multiview Provides more direction for system designers


Star Life Cycle : Star Life Cycle No prescribed ordering of activities Based on actual design practive of HCI designers Emphasis on prototyping and evaluation Rapid prototyping, incremental development


The Star Life Cycle : The Star Life Cycle


Star Life Cycle : Star Life Cycle Conceptual design – what is required? What should system do? What data is required? What will users need to know? Physical design (formal design) : how to achieve the conceptual design …


Methods for UCD : Methods for UCD


Example: Olympic Messaging Service (1984 Los Angeles Olympic Games) : Example: Olympic Messaging Service (1984 Los Angeles Olympic Games) Kiosks at which athletes could send & receive voice messages among themselves Or people from around the world could send messages in to athletes & official Twelve languages (no translation)


OMS - Process : OMS - Process Paper scenarios of user interface prepared Comments from designers, management, prospective users Some functions altered, others dropped Brief user guides prepared, tested, developed iteratively (~200 iteratives) Simulations constructed & evaluated; help messages designed Simulations tested with users


OMS - Process : OMS - Process Needed to add undo/backup button Visit to village site, demos & interviews with ex-olympians & others involved Prototype developed & tested "Hallway" method to collect info on height & layout of prototype kiosk "Try-to-destroy-it" tests of robustness (CS students)


OMS – summary : OMS – summary Focus on users & tasks early in design process, including user guides, help, & ensuring that user's cognitive, social, & attitudinal characteristics are understood & accomodated Measure reactions by using prototype manuals, interface, & other simulations of the system Design iteratively All usability factors must evolve together and be under the responsibility of one control group


Example: Air Traffic Control System : Example: Air Traffic Control System Original system Variety of info needed, each from own source - some on desk, some on ceiling, some not in line of sight Dials Closed Circuit TV Temporary instructions


Air Traffic Control : Air Traffic Control Desire: Integrated data display system SAFETY (major concern) "Upgradeable" Variety of airports/local requirements Modified info requirements Layouts specific to controller & task More color Ability to add pages for specific local conditions Simple editing facilities for updates


Example – Air Traffic Control System : Example – Air Traffic Control System Process: Evaluate controller’s task Develop first-cut design Establish user-systems design group Concept testing, user feedback Produce upgraded prototype Road-show to five airports Develop systems specification build and install system establish new needs