Analysis Stages Overview
| Feasibility Study | Requirements Definition | System Specification |
The Feasibility Study
Objective: To prove the project is practical.
Output:
- A brief description of the proposed system and its characteristics.
- A brief description of the business need for the proposed system.
- A cost/benefit analysis, including gross estimates of schedules and costs, as well
as a payback period.
- A proposed tentative schedule for the delivery of key stage deliverables.
Process:
- Analyze the proposed project and produce a written description.
- Define and document possible types of systems.
- Develop a statement of the probable types of system (centralized, decentralized,
mainframe, etc.).
- Analyze the costs of similar systems.
- Produce a rough estimate of the system size, costs, schedules, etc.
- Define the benefits of the system. Include both quantitative and qualitative
measures.
- Produce an estimate of the next life cycle stage.
- Present feasibility document to clients for discussion.
Deliverables:
- System description (as it is now)
- Project team organization
- Deliverables schedule
- Business need
- Cost-benefit analysis
The Requirements Definition
see requirements example 1
see requirements example 2
see
requirements example 3
Objective: To expand the brief description of the project into a comprehensive set of user-defined specifications.
Output:
An analysis of the current system.
- What is the scope of the proposed system in terms of (a) functions,
- (b) users, (c) dimensions, and (d) constraints?
- A detailed set of user-specified requirements for the new system.
- A summary description of the system.
- Estimates of the next stage of the process.
- An index to all related material.
Process:
- Define the scope of the new system.
Interview all users.
- Determine: (a) their uses of the current system; (b) perceived deficiencies
of the current system; (c) their requirements for the new system.
- Document: (a) current system description; and (b) current deficiencies.
- Analyze current system.
- Draw diagrams of current system (including data flow and entity-relationship
diagrams)
Summarize and critique new system requirements.
- Include: (a) prioritized user requirements; and (b) resolution of current
system's deficiencies.
Produce a list of benefits.
- Include both tangible and intangible benefits; include both quantitative and
qualitative benefits.
Estimate the next stage.
- Produce detailed estimate of costs, schedules, resources, and the like,
including a schedule for the production of major deliverables.
- Produce requirements definition document.
- Final review of document.
Deliverables:
- Analysis of current system
- New system requirements
- Description of new system (perhaps with a prototype)
- Estimates for the next and subsequent stages
- Index to related material
Review Points:
- Scope of the new system
- Analysis of current system
- New system requirements
- Tangible and intangible benefits
- Requirements definition document
-
The System Specification
Objective: To translate the user requirements into more information systems/technology
language.
Output:
- System description
- Data requirements
- Network and telecommunications requirements
- System controls (password access, recovery/restart, etc.)
- Revised cost/benefit analysis and payback schedule
- Estimates of the next stage and remainder of project
Process:
- Define the type of system
- Consider the physical, environmental, and operational constraints into
system constraints.
- Evaluate possibilities such as on-line, transation-based, distributed,
centralized, terminals, workstations, etc.
- Draw diagrams of proposed system (including data flow and entity-relationship
diagrams)
Develop system data dictionary
- Describe all elements on diagrams above, including functions and data.
- Document all interfunction and interdata relationships.
- Ensure compatibility with corporate data dictionary.
Review and expand cost-benefit analysis
- Update previous estimates with new data.
- Estimate next stage
- Produce system specifications document
- Review system specification document
Deliverables:
Alternative system descriptions
Include detailed system description, including descriptions and
specifications of the following:
- Programs, reusable modules and objects
- Files and databases
- Records and transactions
- Data dictionary
- Procedures
- Schedules and timings
- Interfaces (both human and machine)
- Data requirements
- Revised cost-benefit analysis
- Recommended design alternatives: prototyping techniques, phased development,
etc.
- Recommended implementation techniques, self code purchased packages, or
external development
- Preliminary system test plan
- Management summary of proposed system
- Index to related material
- Network and telecommunications requirements
- System controls
Review Points:
- Definition of the new system
- System schematic and system data dictionary
- Updated cost/benefit analysis
- System specification document
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