1 / 23

Requirements Gathering

Requirements Gathering. CSCI 4800/6800 Feb. 25, 2003. Goals. What does the client want/need? (goal: go from vague to specific) Representation of problems with current system Representation of requirements of new system . Techniques. Interviewing/questionnaires Observation

kylemore
Download Presentation

Requirements Gathering

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Requirements Gathering CSCI 4800/6800 Feb. 25, 2003

  2. Goals • What does the client want/need? (goal: go from vague to specific) • Representation of problems with current system • Representation of requirements of new system

  3. Techniques • Interviewing/questionnaires • Observation • Document analysis • Prototyping • Checklists

  4. Types of Requirements • Functional - what system must do • Data - structure of system or data neccessary • Usability - acceptable levels of user performance & satisfaction

  5. Functional Requirements • Both human & system • Dataflow diagrams • Data dictionaries

  6. Data Requirements • Entity-Relationship diagrams

  7. Usability requirements • Learnability • Throughput • Flexibility • Attitude

  8. Functional Requirements • What the system does • What the user does • Result of analysis & collecting requirements is functional specification • Dataflow diagrams • Document or other representation • Separate modules • Organized hierarchically

  9. Functional Requirements • Databases - more persistent than dataflows • An abstraction of the existing system, not a copy of the current physical process • Basis for structured walkthrough - verbal description of the system based on the diagrammatic representation • Other approaches: • Flow charts • Scenarios - good for HCI

  10. Data Requirements • Attention on structure rather than processing • Elicit using • Observation • Document analysis • Interviewing • etc.

  11. Data Requirements • Entity-Relationship (ER) diagrams used with formal descriptions of data elemtents, entities, & relationships kept in a data dictionary, to describe structure & context of the data in a system • Entity - aggregation of a number of data elements (attributes of the entity) • Entity type - classification according to shared attributes/attribute types • Relationships - association between two or more entities

  12. Usability requirements • Easy to learn & remember, Useful, Easy & pleasant to use • Learnability • Time/effort to reach specified level • Throughput • Tasks accomplished by experienced users • Speed of task execution • Errors made • Flexibility • Extent to which system can accommodate changes • Attitude

  13. Determining usability requirements: • Task analysis – (next section) • determine cognitive and other characteristics required of users by system (search strategy, prereq knowledge, cognitive loading, etc.) • User analysis – • determine scope of population who will use the system – user modeling techiques may be applied here; typically use checklists • Environment analysis • where system will operatre

  14. Task Analysis • determine cognitive and other characteristics required of users by system • search strategy • prereq knowledge • cognitive loading • etc.

  15. User Analysis • User analysis – • determine scope of population who will use the system • user modeling techiques may be applied here • typically use checklists

  16. Environment Analysis • where system will operate • Physical aspects • User support environment • more

  17. Usability requirements • Expressed as usability metrics • Completion time for specific tasks by specific set or type of user • Number of errors per task • Time spent using documentation

  18. time to complete task % of task complete % complete per unit time success:failure ratio time spent on errors % number of errors number of commands used frequency of doc/help use time spent in help/doc favorable:unfavorable comments number of reps. of failed commands number of successful runs number of failure runs number of times interface misleads user .... & more Usability metrics

  19. Components of usability • Learnability • time and effort required to reach a specified level of use performance (‘ease of learning’) • Throughput • tasks accomplished by experienced users • speed of task execution, number and type of errors • Flexibility • extent to which system can accomodate change • Attitude • do users like it?

  20. Usability study • the act of gathering usability requirements • involves: • task analysis • user analysis • environment analysis

  21. Task analysis • determine characteristics, particularly cognitive characteristics, required of users by system • search strategy • pre-req knowledge • cognitive loading

  22. User analysis • determine scope of user population that will use system • intellectual ability, cognitive processing ability, previous experience, physical capabilities • typically a checklist description, rather than chart or diagram as in dataflow and E-R

  23. Environment analysis • physical environment • temperature, humidity, lighting, available space • social environment • quiet/loud, busy/isolated, etc. • user support environment • helpful/hostile

More Related