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2 ISA&D7‏/8‏/2013 The Analysis Phase System Requirements Models and Modelling of requirements Stakeholders as a source of requirements

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4 ISA&D7‏/8‏/2013 Gathering information involves: Understanding the existing system Identifying all current and future users, locations, system interfaces (inside and outside the organization) Identifying possible software package solutions that might be used

5 ISA&D7‏/8‏/2013 Prioritize Requirements Establish which functional and technical requirements are most critical Why prioritize Because resources are always limited and you want to address the most important things System requirements tend to expand as users make more suggestions (called “scope creep”)

6 ISA&D7‏/8‏/2013 If system involves new technology, the team may need to get experience working with it. Creating prototypes can be very valuable Prototyping helps to understand possibilities and limitations of the technology By showing prototypes to end users can get feedback into what is really needed Prototypes help users (and analysts) to discover requirements they might not thought about otherwise

7 ISA&D7‏/8‏/2013 Could include considering more than one method to develop system Could involve in-house development or outsourcing to a consulting firm Might be able to use “off the shelf” software package Each alternative has costs and benefits to be considered

8 ISA&D7‏/8‏/2013 Usually done when all the above are completed Must decide if project should continue at all Must decide on which alternative is the best

9 ISA&D7‏/8‏/2013 System requirements – specifications that define the functions of the new system Two sets of requirements: Functional requirements Nonfunctional requirements‏

10 ISA&D7‏/8‏/2013 Functional requirements Activities system must perform (use cases)‏ Based on procedures and business functions Documented in analysis models Non-functional requirements Technical requirement – hardware and software Performance requirement – workload measures Usability requirement – user interface, workflow Reliability requirement – outages, error detection Security requirement – access & protection

11 ISA&D7‏/8‏/2013 Requirements are describes by a collection of models Reasons for modelling

12 ISA&D7‏/8‏/2013 Different types of models are used in information systems development Mathematical Mathematical – formulas that describe technical aspects of the system (e.g., processing rules) Descriptive Descriptive – narrative memos, reports, or lists that describe aspects of the system Graphical Graphical – diagrams and schematic representations of some aspect of the system

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14 ISA&D7‏/8‏/2013 People with interest in successful system implementation Three primary groups of stakeholders Users (use system) Clients (pay for and own system) Technical staff (ensure system operation)

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17 ISA&D7‏/8‏/2013 Thank you ??????