IS Analysis and Design

SDLC Systems Development Life Cycle Break problems into management review stages Control cost and time Works best with well understood systems

SDLC: Zachman Framework

Initial Investigation What is the system supposed to do and what priority should we give it? On IS budget Memo or oral Define user’s general expectations Rough cost Assign priority

How do we find problems? Surveillance Reaction Opportunistic Frameworks Competitive strategy Customer resource life cycle/future perfect Object System rather than IT system

SDLC Waterfall Identify Problem Analyze Current System Determine Information Requirements Design Technology Requirements Develop, Test, & Validate Install Evaluate & Maintain

Identify Problem Analyze Current System Determine Information Requirements Design Technology Requirements Develop, Test, & Validate Install Evaluate & Maintain Feasibility Study

General Analysis Identify Problem Analyze Current System Determine Information Requirements Design Technology Requirements Develop, Test, & Validate Install Evaluate & Maintain

General Analysis Specify logical system requirements

General Systems Analysis Understand the current system Be sure you don’t omit essential features Obtain detailed specifications of expected functions Operations level requirements Provide specifications for IT developers to design from

General Analysis Gather information Existing documentation and actions Interviews and questionnaires Structured interviews Define current decision making process Isolate current deficiencies Identify necessary controls and checks

General Analysis Determining Information Requirements Define all functions of the system Most systems should be cross-functional Avoid information overload Many managers do not know what information they need

General Analysis Determining Information Requirements Give users models of new systems Prototypes and models Reconcile user conflicts Joint Application Design Structure the interview process BSP, Critical Success Factors, Ends Means

Include Complete conceptual data model with table instance data, constraints, and volumes Complete logical data flow analysis with module specifications Conceptual network design with volume requirements

General Analysis Is this an information system or a reengineering project? Reengineering requires a mandate to change the way you do business, and requires a major commitment from all participants. Most information systems are written to support existing processes.

System Design Identify Problem Analyze Current System Determine Information Requirements Design Technology Requirements Develop, Test, & Validate Install Evaluate & Maintain

Detailed Conceptual and Physical Design Computer system structure and module specification

Input/Output design Logical data structures and views Data dictionaries System logic definitions System flow Network design charts Documentation

Identify Problem Analyze Current System Determine Information Requirements Design Technology Requirements Develop, Test, & Validate Install Evaluate & Maintain

System Development Build it

Development Structured Code CASE tools Code generators Rapid Application Development Object Oriented development Prototypes

Testing Walkthroughs and code inspection Application test Unit test - each program System test - whole system together Processes and user acceptance

Identify Problem Analyze Current System Determine Information Requirements Design Technology Requirements Develop, Test, & Validate Install Evaluate & Maintain

Installation Introduce into the organization

Implementation Conversion Direct Phased Pilot Parallel Training Operations acceptance

Identify Problem Analyze Current System Determine Information Requirements Design Technology Requirements Develop, Test, & Validate Install Evaluate & Maintain

Maintenance Everything after acceptance

Proposal How Should we do it?

Defining Problems Root cause Magnitude of problem Size of opportunity

Proposal (Feasibility Study) Formal report On user budget What should we do? How should we do it? What should it cost? How will we use it?

Format: May include these sections Title page Table of contents Executive summary Problem statement Analysis of alternatives Cost and benefits Recommendation Request for authorization Appendix

Executive Summary One to three page summary of the report, including costs and recommendations. Objective: Get the decision maker to refer the rest of the study for detailed analysis.

Problem Statement Simple statement of what is to be accomplished and any major constraints.

Analysis Describes what has been done Indicate alternatives considered Include “do nothing” option and costs Consider purchased products and outsourcing

Analysis (cont.) Technical feasibility Do we have the technology to accomplish this task? Economic feasibility Do the benefits of this project outweigh the costs at this time? Operational feasibility? Does this system fit into the way we want to do business?

Costs and Benefits Costs are easier to identify than benefits Include intangible and tangible costs Business benefits include reduced costs and increased revenue Include competitive positioning Consider business focus: low cost, differentiation, focus

Recommendation Choose the best option. Consider business as well as technical arguments. You may leave some options or a choice between equivalent systems

Request for Authorization Ask permission to continue to next stage Estimate cost and schedule for next stage, as well as total project costs.

Appendices Include Interview notes Document summaries Diagrams and specifications Cost details You may choose not to circulate the appendices with the document if they are long.