Investigating System Requirements Chapter 2

Where are we? Analysis Chapters Ch 2 Investigating System Requirements Use Cases Ch 4 Domain Modeling Ch 5 Use Case Modeling

Outline Stakeholders SDLC Core Process 3 – Analysis Information Gathering Techniques Types of Requirements FURPS+

Stakeholders "Who do you involve and talk to?" Internal Stakeholders External stakeholders Operational stakeholders regularly interact with system Executive stakeholders don’t directly interact but .. use the info , or have financial interest

SDLC Phase: Analysis Core Process 3: Discover & understand details

SDLC Phase: Analysis Gather detailed info Information Gathering Techniques Interviews Observation Review documents & procedures Questionnaires Research vendor solutions User feedback Why do we use different Techniques? Formal Systems Informal Systems

Information Gathering Techniques Interviews Interview users & other key stakeholders Effective way to understand business functions and rules Disadvantage time consuming resource expensive Tips: Plan the interview Stay on schedule!! Interview several key people together (pros & cons) Listen carefully and take notes Be neutral Seek diverse views

Checklist for Conducting an Interview

Information Gathering Techniques Observations Direct Observation Watching users do their jobs Firsthand & objective Disadvantage People may change their normal operating behavior. Time-consuming

Information Gathering Techniques Review Documents & Procedures Existing business documents Forms, reports, work procedures Input & outputs Types of information to be discovered: Reasons for current system design Rules for processing data Problems with existing system Discrepancies, Redundancies Opportunity to meet new need Special information processing circumstances

Information Gathering Techniques 905 Questionnaires Used with a large number of stakeholders Closed-ended & open-ended questions Quantitative data vs. Qualitative data Research Vendor Solutions Many problems have been solved by other companies + provide new ideas, cheaper, less risky - may purchase before understanding problem User Feedback Collecting feedback after initial testing Comments & suggestions

SDLC Phase: Analysis Define requirements System Requirements - (def) specifications that define the new system Functional Requirements - activities the system must perform Non-Functional Requirements - constraints and performance goals Functional Usability Reliability Performance Security + requirements requirements requirements requirements requirements Business rules & processes UI Design Navigation Help Doc. Avail. reqs Failure rate Backup & recovery Response time real time -batch Access controls Encryption Model - a representation of some aspect of a system Textual model Graphical models Mathematical models

SDLC Phase: Analysis Prioritize requirements Develop UI Dialogs High vs. low priority Scope creep Develop UI Dialogs Prototype Can be better than an abstract model Evaluate Requirements with users