User-Centered Development Methodology A user interface comprises those

User-Centered Development Methodology A user interface comprises “those aspects of the system that the user comes in contact with. ” ●Moran [1981]

User-Centered Development Methodology ● Centered on the USER not the Data – – ● Involves users in the whole process Usability can be quantified =>measured Interdisciplinary – ● Draws from many disciplines Highly iterative – Involves repeated testing and revision – Techniques to test and debug interfaces before implementing them

Fields HCI builds upon ● Computer Science – ● Engineering – ● Design for human factors Graphic design – ● Faster, cheaper equipment Ergonomics – ● Implementation of website or other interface Visual communication Technical writing – Textual communication

Fields HCI builds upon ● Linguistics, artificial intelligence – ● Cognitive psychology – ● Perception, memory, mental models Sociology – ● Speech recognition, natural language processing How people interact in groups Anthropology – Study of people in their work settings A highly eclectic field which offers both challenges and satisfactions

User-Centered Methodology ● Initial stages involve gathering of information ● ● ● Needs Analysis User and task analysis Functional analysis Requirements analysis Setting usability specifications Later stages involve designing, building, and testing ● ● Design Prototyping Implementation Evaluation

Needs analysis ● Summarizes the nature and purpose of the system – – – ● Type of system (website, video game, spreadsheet) People it will serve Benefits it will provide This is normally very brief. Two or three sentences explaining why it is a good idea.

User and task analysis ● User analysis - characterizes those who will use the site: – – ● General considerations (age, education, experience with computers) Users' experience and expectations Task analysis - what users will do – – User’s goals - what they want to accomplish Tasks or activities carried out to achieve the goals

Functional analysis ● Functionality -computer services needed by users – ● What to automate – ● on-line reservation or phone call Examples: travel site task: “find all flights to xyz, ordered by price” – ● Close correspondence between functions and tasks Needs search function and sorting capability Music CD site: task “buy a CD” – Needs secure on-line transaction functionality

Requirements analysis ● Describes the formal specifications required to implement the system: – – – ● Data dictionaries Entity-relationship diagrams Object oriented modeling Covered in great detail in software engineering courses.

Setting usability specifications ● ● Answers question “How good is your site? ” Set usability specifications: – Performance measures: Observable user behavior such as number of tasks completed, number of errors, etc. – Preference measures insights into user opinion about site such as first impression, overall satisfaction.

Design Make decisions about: ● Organization – – – ● Visual organization to create clarity and consistency Layout navigation Appearance – “Look and feel” Now you can begin to sketch the pages ● Because you know your users and what they want to do

Prototyping ● Prototype is an original model or pattern – – ● Global: entire site Local: selected parts of the site Prototypes – – Evolutionary: becomes the final project Throw-away: serves as a pattern High fidelity: resembles final product Low fidelity: just rough sketch - not close to final

A low-fidelity prototype

A high-fidelity prototype

Implementation ● This is where the website or other interface is implemented, in HTML or a programming language

Evaluation ● Expert-based evaluation – ● User-based evaluation – ● Bring in a usability expert Test the website or other interface with users In this class we will emphasize user-based evaluation

User-Centered Characteristics ● Highly iterative NO YES

User-Centered Design ● ● ● Is industry-proven Lets you build websites or interfaces that meet user expectations Leads to cost-effective and timely implementation Is highly interactive You have also learned that HCI is a highly eclectic field, building on a dozen other disciplines