Systems Analysis Fundamentals

Systems Analysis

• Systems analysis is a problem-solving method that breaks a system down into its parts to study how they function and interact.

Requirements Discovery

• Requirements discovery is the process of systems analysts identifying system problems and solution requirements from users.

System Requirement

• A system requirement is a property or function that an information system must have, and also called a business requirement.

PIECES Classification of System Requirements

• PIECES is a classification of system requirements

Performance Requirement

• Performance requirement represents the performance levels needed to meet user needs.

Information Requirement

• Information requirement represents information relevant to users based on its content, timeliness, format and accuracy.

Economy Requirement

• Economy requirement represents the system's necessity to cut costs or raise profits.

Control and Security Requirement

• Control and Security requirement represents the system environment, security type, and the degree of security needed.

Efficiency Requirement

• Efficiency requirement represents the system's capability to maximize outputs while minimizing waste.

Service Requirement

• Service requirement represents needs for the system to be reliable, flexible, and expandable.

Results of Incorrect Requirements

• Inaccurate specifications can be delivered in systems that exceed budget.
• Inaccurate specifications can be delivered in systems that are delivered late.
• Systems may not meet user expectations, leading to dissatisfaction and disuse
• The cost of maintaining a system with inaccurate specifications can become exceedingly high once in production.
• Systems may be unreliable, experience frequent errors, and have increased downtime
• Failure is viewed as a mistake which leads to damage to the IT staff's reputation.

Criteria to Define System Requirements

• Requirements should be consistent without conflicts or ambiguities.
• Requirements should be complete by describing all possible system inputs and responses.
• Requirements should be feasible based on available resources and constraints.
• Requirements should be compulsory and fulfill their intended purpose.
• Requirements should be accurate.
• Requirements should be mapped to system functions and features.
• Requirements should be verifiable through testing.

Model-Driven Analysis

• Model-driven analysis is an approach to problem-solving using pictorial system models to document and validate systems.
• The system model becomes the blueprint for designing and building an improved system.
• A model displays a representation of reality or vision.
• Pictures are used to represent reality or vision.

Structured Analysis

• Structured analysis is a process-centered technique used to analyze a system or define business requirements, using models.
• Models are pictures that show a system's processes, inputs, outputs, and files.

Information Engineering (IE)

• Information engineering (IE) is a technique for planning and designing information systems.
• IE is model-driven, data-centered, and process-sensitive.
• IE models show and synchronize the system's data and processes.

Object-Oriented Analysis (OOA)

• Object-oriented analysis is a model-driven method which incorporates data and process aspects into constructs called objects.

Accelerated Systems Analysis Approaches

• Accelerated systems analysis emphasizes building prototypes to quickly determine business and user requirements for a new system.

Discovery Prototyping

• Discovery prototyping helps identify user's business needs by having them interact with a preliminary implementation of those needs.
• A prototype is a small-scale, incomplete working example of the desired system.
• Prototypes support the "I'll know what I want when I see it" way of thinking.
• Focus on the design and commitment can be encouraged prematurely.
• There can be premature preoccupation with the final "look and feel".
• Prototyping tools can mislead users into thinking the completed system will be built rapidly.

Rapid Architected Analysis

• Rapid Architected Analysis is an approach for deriving system models from existing systems or discovery prototypes.

Reverse Engineering

• Reverse engineering uses technology to read program code (database, application, user interface) and automatically produce a system model.