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F28SD2 Software Design Information Systems Lifecycle

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Presentation on theme: "F28SD2 Software Design Information Systems Lifecycle"— Presentation transcript:

1 F28SD2 Software Design Information Systems Lifecycle
Introduction to Feasibility Studies Monica Farrow EM G30 Material available on Vision

2 Timetable Thu Mar 5 G44 Tue Mar 10 NS136
Thu Mar 12 – No lecture – work independently Tue Mar 17 – guest visitor starting at 11:15 (?) Lyle Barbour from SOPRA group Maybe lasting up to 1hr 30 mins Location to be arranged Thu Mar 19 G44 Tue Mar 24 NS136 back with CS 01/13/09 F28SD Software Design

3 Process models There are various types of software lifecycle models
Waterfall, spiral, agile... 01/13/09

4 Waterfall process model
Requirements capture System and software design Implementation and unit testing Integration and system testing You’ll find slightly different versions elsewhere. Operation and maintenance 01/13/09 F28SD Software Design

5 Boehm’s spiral model 01/13/09 F28SD Software Design 5

6 SCRUM – an agile process
Other diagrams show 2-4 weeks Rather than 30 days 01/13/09

7 Information Systems lifecycle
Software lifecycle models concentrate on design and implementation of a software system models lack an overall picture of the organisation and its business processes A traditional structured design method extended in this manner is shown next (Based on Avison and Shah) The similarities are clear So are the new features 01/13/09 F28SD Software Design

8 Information Systems lifecycle After Avison and Shah p71 IS planning
Problems with existing system New business opportunities Information Systems lifecycle After Avison and Shah p71 IS planning Managerial directive Feasibility study Feasibility study report Systems investigation User requirements Project plans Resource requirements Staff assignment Methods and tools Systems analysis Current system data flow System requirements Systems design New system data flow System specification Training and test plans Implementation Programs Procedures Documentation New system in operation Review and maintenance Evaluation report New problem statement? 01/13/09 F28SD Software Design

9 What’s similar? Stages rather like waterfall
Repeats with review like spiral Progress in terms of artefacts 01/13/09 F28SD Software Design

10 What’s added? Feasibility study Review during maintenance
System is an open one Operation feeds back to design 01/13/09 F28SD Software Design

11 Review during maintenance
Learning from experience Effectiveness of the solution Correctness of function Efficiency Suitability for the business process Effectiveness of the process Kept to time? Kept to budget? Lessons learned for future developments 01/13/09 F28SD Software Design 11

12 System is an open one Take account of influences from the organisation which change over time Managerial directives often arbitrary but often dominate decision making New opportunities business process change requires system change Longer term information systems planning system change to maintain business process 01/13/09 F28SD Software Design 12

13 Operation feeds back to design
Operation reveals errors - “maintenance” in SE Operation reveals bottlenecks for the business Operation reveals new opportunities for business Operation reveals difficulties for users Summary : from the original ‘build a system then hand it over’ approach, we must be now more aware of the user and their environment. 01/13/09 F28SD Software Design 13

14 The negative option is a valid option!
Feasibility study Propose and evaluate alternatives Establish priorities Gather information Perform cost-benefit analysis Form options for computerisation Present conclusions The negative option is a valid option! 01/13/09 F28SD Software Design 14

15 Objectives of feasibility study
A feasibility study should provide management with enough information to decide: whether the project can be done whether the final product will benefit its intended users what are the alternatives among which a solution will be chosen (during subsequent phases) is there a preferred alternative After a feasibility study, management makes a go/no go decision The feasibility study is a management-oriented activity 01/13/09

16 Inputs and outputs Organisation Feasibility study Users Management
report Existing Practice Boundary Constraints Objectives Responsibilities New Opportunities Problems New Requirements Feasibility study Systems analyst Suppliers Costs 01/13/09

17 Terms of reference Project objectives System boundary Responsibility
Constraints Reporting mechanism 01/13/09

18 Terms of reference Project objectives System boundary
Unambiguous statement of what the client expects Must be agreed before further work is done System boundary The scope of the feasibility study What should be considered What should not be considered 01/13/09

19 Terms of reference continued
Responsibility Who will supervise the project? Who can authorise changes during the study? Is the scope fixed? Constraints Budget Time scales Resources Etc Reporting How will the report be expected? To whom will the report be presented? Who else can see the report? 01/13/09

20 Tasks in conducting the study
Study current situation Analyse requirements Consider alternatives Analyse economic/financial situation 01/13/09

21 Current situation Study current situation
The present organizational system, including users, policies, functions, objectives,... Problems with the present system (inconsistencies, inadequacies in functionality, performance,..., Gain thorough understanding Establish reality of problems Look for opportunities Establish cause and effect 01/13/09

22 PIECES framework The PIECES framework can help in identifying problems to be solved, and their urgency: Performance -- Does current mode of operation provide adequate throughput and response time? Information -- Does current mode provide end users and managers with timely, pertinent, accurate and usefully formatted information? Economy -- Does current mode of operation provide cost-effective information services to the business? Could there be a reduction in costs and/or an increase in benefits? 01/13/09

23 PIECES framework Control -- Does current mode of operation offer effective controls to protect against fraud and to guarantee accuracy and security of data and information? Efficiency -- Does current mode of operation make maximum use of available resources, including people, time, flow of forms,...? Services -- Does current mode of operation provide reliable service? Is it flexible and expandable? 01/13/09

24 Analyse requirements Analyse requirements (What not how)
Objectives and other requirements for the new system what needs to change? What would the stakeholders like to achieve? Constraints, including non-functional requirements on the system (preliminary pass) What is the client’s intention? What capabilities are needed? Data input and stored Information output 01/13/09

25 Tasks in conducting the study continued
Consider alternative solutions Possible alternatives (the current system is always one of those) Different business processes for solving the problems Different levels/types of computerization for the solutions Advantages and disadvantages of the alternatives Economic/financial analysis Costs of alternatives Opportunity costs of inaction Benefits of changes Impact on business as a whole 01/13/09

26 Four tests for feasibility
There are four categories of feasibility tests Operational feasibility How well will solution work in organisation? How do people feel about it? Technical feasibility Practical? Expertise? Schedule feasibility Reasonable timetable? Economic feasibility Cost-effective? 01/13/09

27 Operational Feasibility: Acceptability
How do end-users and managers feel about the problem (solution)? It's not only important to evaluate whether a system can work but also evaluate whether a system will work. A workable solution might fail because of end-user or management resistance. Does management support the project? How do the end-users feel about their role in the new system? What end-users or managers may resist or not use the system? People tend to resist change. Can this problem be overcome? If so, how? How will the working environment of the end-users change? 01/13/09

28 Operational Feasibility: Acceptability
Can or will end-users and management adapt to the change? Internal issues, such as manpower problems, labour objections, manager resistance, organizational conflicts and policies; also external issues, including social acceptability, legal aspects and government regulations. The PIECES framework can also be used for each alternative solution Performance, Information, Economy, Control, Efficiency, Services 01/13/09

29 Technical feasibility
Is the proposed technology or solution practical? Do we currently possess the necessary technology? Do we possess the necessary technical expertise, and Is the schedule reasonable for the team? Is relevant technology mature enough to be easily applied to our problem? Is it compatible with our other systems? 01/13/09

30 Technical feasibility
Some firms like to use state-of-the-art technology, but most firms prefer to use mature and proven technology. A mature technology has a larger customer base for obtaining advice concerning problems and improvements. Assuming that required technology is practical, is it available ‘in-house’? If so, does it have the capacity to handle the solution. If not, can it be acquired? Is it available within given resource constraints (i.e., budget, schedule,...)? 01/13/09

31 Schedule feasibility Do we have the skills required to properly apply that technology; True, all information systems professionals can learn new technologies; However, that learning curve will impact the technical feasibility of the project; Specifically, it will impact the schedule. Given our technical expertise, are the project deadlines reasonable? Some projects are initiated with specific deadlines; You need to determine whether the deadlines are mandatory or desirable. What are the consequences of delay? If the deadlines are desirable rather than mandatory, the analyst can propose alternative schedules. Missed schedules are bad, but inadequate systems are worse! 01/13/09

32 Economic feasibility The bottom line in many projects is economic feasibility. During the early phases of the project, economic feasibility analysis amounts to little more than judging whether the possible benefits of solving the problem are worthwhile. As soon as specific requirements and solutions have been identified, the analyst can weigh the costs and benefits of each alternative. This is called a cost-benefit analysis. 01/13/09

33 Cost/benefit analysis
The purpose of a cost/benefit analysis is to answer questions such as: Is the project justified (because benefits outweigh costs)? Can the project be done, within given cost constraints? What is the minimal cost to attain a certain system? What is the preferred alternative, among candidate solutions? 01/13/09

34 Cost/benefit analysis
Examples of things to consider: Hardware/software selection How to convince management to develop the new system Selection among alternative financing arrangements (rent/lease/purchase) Difficulties Discovering and assessing benefits and costs. They can both be intangible, hidden and/or hard to estimate, It's also hard to rank multi-criteria alternatives 01/13/09

35 Types of benefit Examples of particular benefits: cost reductions,
error reductions, increased throughput, increased flexibility of operation, Improved operation, better (e.g., more accurate) and more timely information 01/13/09

36 Types of benefit Benefits may be classified into one of the following categories: Monetary -- when $-values can be calculated Tangible (Quantified) -- when benefits can be quantified, but $-values can't be calculated Intangible -- when neither of the above applies How to identify benefits? By organizational level (operational,lower/middle/higher management) or by department (production,purchasing, sales,...) 01/13/09

37 Types of cost Project-related costs Development and purchasing costs:
who builds the system(internally or contracted out)? software used (buy or build)? hardware (what to buy, buy/lease)? facilities (site, communications, power,...) Installation and conversion cost installing the system, training of personnel, file conversion,.... 01/13/09

38 Types of cost Operational costs (on-going) Maintenance
hardware (maintenance, lease, materials,...), software (maintenance fees and contracts), facilities Personnel: operation, maintenance 01/13/09

39 Types of cost For a small business that wants to introduce a PC-based information system, these cost categories translate to the following: Project costs purchasing (hardware, software, office furniture), customizing software, training, system installation and file conversion On-going costs: operating the system (data entry, backups, helping users, vendors etc.), maintenance (software) and user support, hardware and software maintenance, supplies 01/13/09

40 Costing example? 01/13/09

41 Next More on costs next time
Most of these notes come from Ch9 of Systems Analysis and Design Methods b Whitten, Bentley and Dittman You can read this chapter in full electronically, on Vision 01/13/09

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