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Chapter Five Objectives:. What are information systems, and who are the stakeholders in the information systems game?Define systems analysis and relate the term to the preliminary investigation, problem analysis, requirements analysis, and decision analysis phases of the systems development methodo
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2. Chapter Five Objectives: What are information systems, and who are the stakeholders in the information systems game?
Define systems analysis and relate the term to the preliminary investigation, problem analysis, requirements analysis, and decision analysis phases of the systems development methodology.
Describe a number of systems analysis approaches for solving business system problems.
Describe the preliminary investigation, problem analysis, requirements analysis, and decision analysis phases in terms of your information system building blocks.
Describe the preliminary investigation, problem analysis, requirements analysis, and decision analysis phases in terms of purpose, participants, inputs, outputs, techniques, and steps.
Understand the importance of never making assumptions!
3. Systems Analysis vs. Systems Design Systems analysis is a problem-solving technique that decomposes a system into its component pieces for the purpose of studying how well those component parts work and interact to accomplish their purpose.
Systems design (also called systems synthesis) is a complementary problem-solving technique (to systems analysis) that reassembles a system’s component pieces back into a complete system—hopefully, an improved system. This may involves adding, deleting, and changing pieces relative to the original system.
4. Information Systems Analysis Information systems analysis is defined as those development phases in a project that primarily focus on the business problem, independent of any technology that can or will be used to implement a solution to that problem.
5. Repository A repository is a location (or set of locations) where systems analysts, systems designers, and system builders keep all of the documentation associated with one or more systems or projects.
A network directory of computer-generated files that contain project correspondence, reports, and data
A CASE tool dictionary or encyclopedia
Printed documentation (binders and system libraries)
An intranet website interface to the above components
6. Never Make Assumptions: Nativity Scene Christmas season - independent of religious beliefs, the most recognized icon of the season is the Nativity scene.
Take a moment to review the typical Nativity scene in your head.
Try to describe all of the elements of the scene. Have you seen it so much that you can’t properly remember all of the pieces??
What is the correct description? Where do we find it?
7. Model-Driven Analysis Methods Model-driven analysis emphasizes the drawing of pictorial system models to document and validate both existing and/or proposed systems. Ultimately, the system model becomes the blueprint for designing and constructing an improved system.
A model is a representation of either reality or vision. Just as “a picture is worth a thousand words,” most models use pictures to represent the reality or vision.
8. Model-Driven Methods Structured analysis is a model-driven, process-centered technique used to either analyze an existing system, define business requirements for a new system, or both. The models are pictures that illustrate the system’s component pieces: processes and their associated inputs, outputs, and files.
Information engineering (IE) is a model-driven and data-centered, but process-sensitive technique to plan, analyze, and design information systems. IE models are pictures that illustrate and synchronize the system’s data and processes.
Object-oriented analysis (OOA) is a model-driven technique that integrates data and process concerns into constructs called objects. OOA models are pictures that illustrate the system’s objects from various perspectives such as structure and behavior.
9. A Simple Process Model
10. A Simple Data Model
11. A Simple Object Model
12. Accelerated Analysis Methods Accelerated analysis approaches emphasize the construction of prototypes to more rapidly identify business and user requirements for a new system.
A prototype is a small-scale, incomplete, but working sample of a desired system. Prototypes cater to the “I’ll know what I want when I see it” way of thinking that is characteristic of many users and managers.
13. Accelerated Analysis Methods Discovery prototyping (sometimes called requirements prototyping) is used to identify the users’ business requirements by having them react to a quick-and-dirty implementation of those requirements.
Rapid architecture analysis is an approach that attempts to derive system models (as described earlier in this section) from existing systems or discovery prototypes.
Reverse engineering technology reads the program code for a database, application program, and/or user interface and automatically generates the equivalent system model.
14. Requirements Discovery Methods Requirements discovery includes those techniques to be used by systems analysts to identify or extract system problems and solution requirements from the user community.
Fact-finding (or information gathering) is a classical set of techniques used to collect information about system problems, opportunities, solution requirements, and priorities.
Sampling
Research
Observation
Questionnaires and surveys
Interviews
Joint requirements planning (JRP) techniques use facilitated workshops to bring together all of the system owners, system users, systems analysts, and some systems designer and builders to jointly perform systems analysis.
15. Business Process Redesign Methods Business process redesign is the application of systems analysis methods to the goal of dramatically changing and improving the fundamental business processes of an organization, independent of information technology.
16. Systems Analysis Phases Preliminary Investigation Phase
Problem Analysis Phase
Requirements Analysis Phase
Decision Analysis Phase
17. Cause-and-Effect Analysis Cause-and-effect analysis is a technique in which problems are studied to determine their causes and effects.
In practice, effects can be symptomatic of more deeply rooted or basic problems which, in turn, must be analyzed for causes and effects until such a time as the causes and effects do not yield symptoms of other problems.
18. System Improvement Objectives An objective is a measure of success. It is something that you expect to achieve, if given sufficient resources.
Reduce the number of uncollectible customer accounts by 50 percent within the next year.
Increase by 25 percent the number of loan applications that can be processed during an eight-hour shift.
Decrease by 50 percent the time required to reschedule a production lot when a workstation malfunctions.
A constraint is something that will limit your flexibility in defining a solution to your objectives. Essentially, constraints cannot be changed.
19. Business Requirements A functional requirement is a description of activities and services a system must provide.
A nonfunctional requirement is a description of other features, characteristics, and constraints that define a satisfactory system.
20. Logical System Models Logical system models depict what a system is or what a system must do—not how the system will be implemented. Because logical models depict the essential requirements of a system, they are sometimes called essential system models.
Process models (e.g., data flow diagrams)
Data models (e.g., entity relationship diagrams)
Interface models (e.g., context diagrams)
Object models (e.g., Uniform Modeling Language diagrams)
21. A Simple Interface Model
22. Requirements Statement
23. Feasibility Analyses Technical feasibility. Is the solution technically practical? Does our staff have the technical expertise to design and build this solution?
Operational feasibility. Will the solution fulfill the users’ requirements? To what degree? How will the solution change the users’ work environment? How do users feel about such a solution?
Economic feasibility. Is the solution cost-effective?
Schedule feasibility. Can the solution be designed and implemented within an acceptable time period?
24. Automated Tools for Systems Development
25. Learning Objectives Identify the trade-offs when using CASE
Describe organizational forces for and against adoption of CASE tools
Describe the role of CASE tools and how they are used to support the SDLC
List and describe the typical components of a comprehensive CASE environment
Describe the general functions of upper CASE tools, lower CASE tools, cross life-cycle CASE tools and the CASE repository
26. Learning Objectives Describe visual and emerging development tools and how they are being used
27. Introduction Computer-aided Software Engineering (CASE)
Automated software tool used by systems analysts to develop information systems
Used to support or automate activities throughout the systems development life cycle (SDLC)
Increase productivity
Improve overall quality of systems
28. The Use of CASE in Organizations Purpose of CASE is to facilitate a single design philosophy within an organization
29. The Use of CASE in Organizations Objectives of CASE
Improve quality of systems developed
Increase speed of development and design
Ease and improve testing process through automated checking
Improve integration of development activities via common methodologies
Improve quality and completeness of documentation
Help standardize the development process
Improve project management
Simply program maintenance
Promote reusability
Improve software portability
30. CASE and System Quality Majority of organizations adopt CASE to improve speed and quality of systems development projects
Widespread deployment has been slower than expected
31. CASE and System Quality Several factors that inhibit widespread deployment
Cost
Between $5,000 and $15,000 per year to provide CASE tools to one systems analyst
Return on Investment
Biggest benefits of CASE come in late stages of SDLC
Productivity Bottlenecks
Inability of some tools to share information
Difficulty in providing tools for all stages of SDLC
32. The Outlook for CASE Functionality is increasing
Cost is decreasing
Reverse Engineering Tools
Automated tools that read program source code as input and create graphical and textual representations of program design-level information
Reengineering Tools
Automated software that reads program source code, analyzes it and automatically or interactively alters an existing system to improve quality and/or performance
33. Components of CASE Upper CASE
CASE tools designed to support the information planning and the project identification and selection, project initiation and planning, analysis and design phases of the systems development life cycle
Lower CASE
CASE tools designed to support the implementation and maintenance phases of the systems development life cycle
34. Components of CASE Cross life-cycle CASE
CASE tools designed to support activities that occur across multiple phases of the systems development life cycle
Most CASE tools utilize a repository to store all diagrams, forms, models and report definitions
35. Components of CASE Types of CASE tools
Diagramming tools
Computer display and report generators
Analysis tools used to check for incomplete, inconsistent or incorrect specifications
A central repository
Documentation generators
Code generators
36. Components of CASE Security Features
Version Control
Import/Export
Backup and Recovery
37. CASE versus Traditional Systems Development Traditional approach does not offer support for integration of specification documents
Often, documentation is done after coding is completed in traditional systems development
Traditional approach often leads to out- of-date documentation
38. CASE versus Traditional Systems Development Traditional Systems Development
Emphasis on coding and testing
Paper-based specifications
Manual coding of programs
Manual documenting
Intensive software testing
Maintain code and documentation CASE-Based Systems Development
Emphasis on analysis and design
Rapid interactive prototyping
Automated code generation
Automated documentation generation
Automated design checking
Maintain design specifications
39. CASE Diagramming Tools Enable representation of a system and components visually
Effective for representing process flows, data structures and program structures
Several types of diagrams
Data Flow Diagrams (DFD)
Functional Hierarchy Diagrams
Entity-Relationship Diagrams
40. CASE Form and Report Generator Tools CASE tools that support the creation of system forms and reports in order to prototype how systems will look and feel to users
Two Purposes
Create, modify and test prototypes of computer display forms and reports
Identify which data items to display or collect for each form or report
41. CASE Analysis Tools Enable automatic checking for incomplete, inconsistent or incorrect specifications in diagrams, forms and reports.
Types of analyses vary depending on the organization’s development methodology and features of CASE environment
42. CASE Repository Integrated CASE (I-CASE)
Automated systems development environment that provides numerous tools to create diagrams, forms and reports
Provides analysis, reporting and code generation facilities
Seamlessly shares and integrates data across and between tools
Repository is central place to store information to share between tools
43. CASE Repository Holds complete information needed to create, modify and evolve a software system from project initiation and planning to code generation and maintenance
Two Primary Segments
Information Repository
Data Dictionary
44. CASE Repository Information Repository
Combines information about an organization’s business information and its application portfolio
Provides automated tools to manage and control access to repository
Business Information
Data stored in corporate databases
Application Portfolio
Application programs used to manage business
45. CASE Repository Data Dictionary
Computer software tool used to manage and control access to the information repository
Contains all data definitions for all organizational applications
Cross referencing
Enables one description of a data item to be stored and accessed by all individuals
Single definition for a data item is established and used
46. CASE Repository Data Dictionary
Entries have a standard definition
Element name and alias
Textual description of the element
List of related elements
Element type and format
Range of acceptable values
Other information unique to the proper processing of this element
47. CASE Repository CASE Repository and the SDLC
During project initiation and planning phase, all information related to the problem being solved is stored in the repository
Problem domain, project resources, history and organizational context
During analysis and design phases, store graphical diagrams and prototype forms and reports
Data stored in repository are used for basis to generate code and documentation
48. CASE Repository Additional Advantages
Assistance with project management tasks
Aids in software reusability
The ability to design software modules in a manner so that they can be used again and again in different systems without significant modification
49. CASE Documentation Generator Tools Enable the easy production of both technical and user documentation
Allow creation of master templates used to verify that documentation conforms to all stages of SDLC
50. CASE Code Generation Tools Enable the automatic generation of program and database definition code directly from the design documents, diagrams, forms and reports stored in the repository
51. Visual and Emerging Development Tools Object-Oriented Development Tools
Object
A chunk of program and data that is built to perform common functions within a system
Easily reused
Encapsulation
Process of grouping data and instructions together
Development environment includes pre-defined objects and facilitates reuse of code
52. Visual and Emerging Development Tools Visual Development Tools
Enable developers to quickly create user interfaces
Popular tools include:
Microsoft Visual Studio
Delphi
Powerbuilder
ColdFusion
53. Summary Use of CASE in Organizations
Categories of CASE Tools
Reverse Engineering
Re-engineering
Components of CASE
Upper CASE
Diagramming tools
Form and report generators
Analysis tools
54. Break
55.
INFORMATION GATHERING
FOR INFORMATION
SYSTEMS DEVELOPMENT
56. Lecture Objectives to be aware of various methods for data gathering in respect of information system development
to understand the usefulness and suitability of various data gathering methods for particular problem situations
57. Data gathering in systems development Data gathering is a major task of systems analysis.
Systems analysis involves:
Understanding and describing how the current system functions
Determining what users would like their new system to do (requirements)
Need to collect information:
current and future situations, problems, opportunities, constraints
58. Data gathering as a foundation for developing information systems What data?
Sources of data?
What data gathering methods?
What strategy for gathering data is needed?
How will the data gathered be analysed?
59. Data about the business or organisation
Data about the business environment
Data about the system’s environment
Data about the users of the system
Data about the current system
Data about the proposed system
Constraints: e.g. cost, technical,timeframe What data to gather?
60. What data to gather? The business or organisation:
Data about the nature of the business and its market and business environment
Data about business goals and objectives that dictate what and how work is done
Data about organisational structure: major functions, departments etc
Data about major business subsystems and how they interact
Data about business policies and guidelines
61. Users of the system:
Roles and responsibilities
Reporting structures
Job specifications and actual tasks performed
Information needed to do their jobs
Formal and informal communication and workflow channels What data to gather?
62. Users of the system:
Data about roles and responsibilities
Data about reporting structures
Job specifications and data about actual tasks performed
Data about information needed to do their jobs
Data about formal and informal communication and workflow channels What data to gather?
63. The existing system:
Data about tasks and workflow: functions, processes, sequence of processes, methods and procedures, inputs, outputs
Data about the data (definition, volumes, size etc.)
Data about interactions with other systems
Data about work volumes and processing cycles
Data about performance standards and criteria
Data about control mechanisms: e.g security, accuracy
Data about problems: e.g. efficiency, information What data to gather?
64. The new system:
Data about system requirement: a need or desire to be met by a proposed system
Data about both functional requirements (processes and functionality) and
non-functional requirements (security, performance, service etc.)
Data about constraints e.g. existing technology
Data about interactions with other systems
Data about relationship to existing system/s What data to gather?
65. Sources of data Users and other stakeholders
Documents about the system
Documents about the organisation
Documents and data used within the existing system
Transactions within existing system
External sources
66. Users
System sponsor/owner: overall project objectives
Managers: high level, broad view of existing system and requirements
End-users: detailed, operational level view of existing system and requirements
Technical staff: technology capaabilities, limitations etc.
External stakeholders: e.g. customers Sources of data
67. Documents about the system and organisation:
Organisation charts
Policy manuals
Business reports: financial, annual etc.
Jobs, procedure, operations manuals
Training manuals
Existing system documentation
Internal reports relating to the system Sources of data
68. Documents and data used within the existing system:
Files, databases, programs, forms, reports
Informal: Memos, bulletin boards, files
External sources:
Other organisations’ systems
Hardware & software vendors
Business & industry publications
Sources of data
69. Interviews
Questionnaires
Observation
Sampling documents and transactions
Research and site visits
70. Generally the most important and widely-used method for data gathering
May be formal/structured (specific questions) or informal/unstructured (general goal or purpose)
Need an interview strategy for the entire interviewing process
Need an interview plan or guide for each interview
71. The interview strategy Identify the users to interview:
Do this after you have an initial understanding of the organisation and system
Establish general objectives and guidelines for the entire interviewing process:
e.g. information to be obtained, sources, formats, documenting, analysis
Ensure all key people are included
72. Determine the sequence of interviews:
E.g. management first:
broad overview of system operations
gain support and co-operation
help to identify who to interview next
Then system users:
obtain information about detailed operations
Co-ordinate the interviewing process:
Compare results, select follow ups etc. The interview strategy
73. The interview strategy Need individual interview plans:
Initial interviews to meet users
Fact gathering interviews
Follow up interviews
Interview plans:
Decide on interview structure
Determine content of questions
Decide on question types
74. Interviews Need to consider:
Who has the information you need?
Where to conduct the interview?
When is the best time to interview?
How should the interview progress?
75. The individual interview Before the interview:
Arrange time and place, necessary materials, inform interviewee of interview purpose
Conduct the interview
After the interview:
Write an interview report
Review this with the interviewee at a follow up interview
76. The interview structure Preliminaries:
Introduction, purpose, environment and procedures e.g. permission to tape
“Body”:
Define what you already believe to be true and confirm this, explore points & issues further, new areas (questions)
Conclusion:
Summarise and confirm your findings
Schedule a follow up interview
77. Interviews: types of questions Closed: how many transactions per day?
Limits available responses
Open: tell me about …..
Leaves options open for interviewee
Probe: tell me more about the problem with the ….
To clarify and expand
Mirror: From what you said, I understand that….
To confirm what was said etc.
78. Interviews: types of questions Avoid long, complex, or double-barrelled questions:
what decisions are made during this process and how do you make them?
Avoid leading questions;
you don’t need the customer number on this report, do you?
Avoid loaded questions:
when did you first discover the mistake?
i.e. how long have you known and done nothing?
79. Interviews: advantages obtain extensive, complex detailed information
get insights and opinions
discover informal procedures
flexible e.g. explore issues further or new issues
establish rapport with interviewee and understand their attitudes
reveal the ‘politics’ of the system environment
information is revealed both by the spoken word and by the interviewee’s body language
guaranteed response
80. Interviews: Disadvantages Time-consuming
Costly
Danger of bias
More difficult to tabulate and analyse results e.g. to obtain an overall picture
Success in interviewing depends on the inter-personal skills of the interviewer
81. A structured method of data gathering in which written questions/comments are provided for the participants to respond to in written form
The questionnaire can take many forms - write comments/ select from a list of possible responses/ mark on a scale
May permit either quantitative or qualitative data (mark out of 10/grade from good to bad)
Usually involves no direct contact between data gatherer and respondents
82. Questionnaires Useful when small amounts of data are required from a large number of people
For geographically dispersed respondents
Types of questions:
Open-ended (free format)
Fill-in-the-blank
Multiple choice
Rating
Ranking
83. Designing questionnaires What facts and opinions to be collected
Who to sample and sample size
Types of questions and wording (precise, accurate, unambiguous)
How to administer e.g. paper, online, mail out etc.
Format and layout (grouping, crosschecks etc.)
Test on small sample of respondents
How completed questionnaires will be returned and collated
How analysis of the data will be carried out
84. Questionnaires Useful for:
Obtaining simple opinions, facts
Quantifying what was found in interviews
Identifying issues before interviewing
Determining extent of problems
Not useful for detailed or complex information or exploring issues in depth
Can supplement other methods
85. Questionnaires: advantages most economical method for gathering data from large numbers of people
quick and easy to administer
results can be tabulated rapidly and analysed readily
allow respondents to be anonymous
gives respondents time to reflect on answers
respondents complete in their own time
86. Questionnaires: disadvantages difficult to construct effective questionnaires
specific and limited amounts of information
possible low return rates
possible bias and misinterpretation
cannot probe issues further (inflexible)
cannot clarify vague or incomplete answers
lack non-verbal communication
87. Observation observing the actual processes of a system
need to prepare beforehand, and report on data collected
gain first hand knowledge of current system’s operations
clarify other information collected
understand complex procedures
inexpensive
behaviour distortions may affect reliability
unrepresentative samples affect reliability
88. Sampling of documents and transactions Sampling: collecting a representative sample of documents, forms, transactions
Useful for specific information e.g. transaction volumes and types, file sizes
Useful where large volumes exist
Information about existing system operations
Representative samples must be selected:
determine sample size, appropriate range, avoid bias
89. Research and site visits Most problems not unique: learn from experiences of other organisations
Professional societies can provide contacts for site visits
Computer trade journals and magazines and the internet can be sources for research into the problem/s e.g. do appropriate software packages exist?
90. Other data gathering methods Other “modern” methods used:
Discovery prototyping
JAD (Joint Application Development) sessions
Focus groups
91. A data gathering strategy Data gathering must be carefully planned in order to make the most of the time and resources available:
Information sources
Data gathering methods
Recording and documentation methods
Data analysis methods
Procedures for reviewing results with management and users
92. A data gathering strategy E.g. a “top down” approach:
Initial interviews with management to determine major system activities and data
Document and verify this
Expand major system component descriptions into detailed descriptions:
Interview operational users, sampling, questionnaires, observation etc
Document and verify this
Repeat these last two steps as necessary
Review findings with management
93. A data gathering strategy Consider costs: allow for time and resources required for initial and ongoing information gathering
Use the least expensive methods first
Plan how to check the validity of data:
Cross checking between groups, methods
Evaluate data for inconsistencies
Ask further questions
Plan documentation of data e.g. records of interviews etc. data dictionary, system models
94. Data gathering in practice Completeness?
Accuracy?
Objectivity?
Biases?
Stability?
Representative?
Finished?