ISTM 320 Ch 4

System requirement

A characteristic or feature that must be included in an information system to satisfy business requirements and be acceptable to users.

Requirements engineering

Used in the systems planning phase of the SDLC. It involves fact-finding to describe the current system and identify the requirements for the new system.

Gathering requirements

Understanding the problem.

Representing requirements

Describing the problem.

Validating and verifying requirements

Agreeing on the problem.

Requirements definitions

A description of the system requirements from the user's point of view.

Requirements specifications

A description of the system requirements from the analyst or engineering team's point of view.

Functional requirement

A statement of the services a system provides.

Example of functional requirement

Each input form must include the date, time, product code, customer number, and quantity.

Non-functional requirement

A statement of operational system constraints, also known as quality attributes.

Example of non-functional requirement

Response time must be four seconds at most, the system should work on Windows and Mac platforms.

Requirements Challenges

3 of the most important challenges are imprecision, agreement, and creep.

Imprecision

Natural language is expressive but prone to misinterpretation; different stakeholders may disagree on simple requirements.

Agreement

Challenge: stakeholders agreeing on meanings; requirements should be complete and consistent, but hard to fully achieve.

Creep

Business changes lead to more requirements over time; Agile methods handle evolving requirements better than traditional methods.

Scalability

A characteristic of a system implying that it can be expanded, modified, or downsized easily to meet the rapidly changing needs of a business enterprise.

Security

All-important for today's networked systems.

Total cost of ownership

Includes all future operational and support costs.

Joint application development (JAD)

A systems development technique that uses a task force of users, managers, and IT professionals who work together to gather information, discuss business needs, and define the new system requirements.

JAD Project Leader

Facilitates sessions, manages agenda.

Rapid application development (RAD)

A team-based technique that speeds up information systems development and produces a functioning information system.

RAD

RAD is similar in concept to joint application development (JAD) but includes all phases of the systems development life cycle (SDLC).

Iterative Development

Breaks project into smaller phases, each lasting weeks to months.

User Involvement

Users are actively involved throughout the process.

Prototyping

Builds working models to gather feedback and refine designs.

Timeboxing

Each phase has a fixed time frame for rapid progress.

Collaboration

Development team works closely together, often in the same space.

Reusability

Uses prebuilt components to speed up development.

Continuous Integration/Testing

Frequent integration and testing for quality.

Requirements planning phase

A phase that combines elements of the systems planning and systems analysis phases of the SDLC.

User design phase

In this phase, users interact with systems analysts and develop models and prototypes that represent all system processes, outputs, and inputs.

Construction phase

A phase focused on program and application development tasks similar to the SDLC.

Cutover phase

A phase that resembles the final tasks in the SDLC implementation phase, including data conversion, testing, changeover to the new system, and user training.

Agile methods

Systems development methods that attempt to develop a system incrementally by building a series of prototypes and constantly adjusting them to user requirements.

Scrum

A popular technique for agile project management derived from a rugby term, where team members play specific roles and interact in intense sessions.

Requirements elicitation

The process of gathering requirements.

Fact-finding

The process of gathering requirements.

Interview

A planned meeting during which information is obtained from another person.

Leading questions

Queries that suggest or favor a particular reply.

Open-ended questions

Queries that provide a range of answers, encouraging spontaneous and unstructured responses.

Close-ended questions

Queries that limit or restrict the range of responses, used when specific information or fact verification is desired.

Range-of-response questions

Closed-ended questions that ask a person to evaluate something by providing limited answers to specific responses or on a numeric scale.

Engaged listening

The ability to concentrate on what someone is saying and avoid the temptation to hear what is expected, including noticing nonverbal communication.

Document review

A review of baseline documentation, a useful fact-finding technique that helps an analyst understand how the current system is supposed to work.

Observation

A fact-finding technique in which an analyst sees a system in action, allowing the verification of statements made in interviews.

Hawthorne Effect

A phenomenon in which employees who know they are being observed are more productive.

Questionnaire (survey)

A document containing several standard questions that can be sent to many individuals.

Fill-in form

A template used to collect data on the Internet or a company intranet

Brainstorming

A fact-finding technique for gaining information through a small group discussion of a specific problem, opportunity, or issue

Structured brainstorming

A group discussion in which each participant speaks when it is their turn or passes

Unstructured brainstorming

A group discussion in which any participant can speak at any time

Sampling

A process in which an analyst collects examples of actual documents, including records, reports, or various forms

Systematic sampling

A sample that occurs at a predetermined periodicity. For example, every tenth customer record might be selected as a systematic sample for review

Stratified sample

A sample in which a set metric is collected across functional areas. For example, a certain percentage of transactions from every work shift, or five customers from each of four postal codes, could be a stratified sample

Random sample

A selection taken in an arbitrary, unplanned manner—for example, a sample that selects any 20 customers

Research

An important fact-finding technique that includes reviewing journals, periodicals, and books to obtain background information, technical material, and news about industry trends and developments

Site visit

A trip to a physical location to observe a system in use there

Iterative and Incremental

Requirements gathered gradually with each software increment

Collaboration

Frequent communication between the team and stakeholders (e.g., daily stand-ups, sprint reviews)

Adaptive

Requirements evolve and adapt as the project progresses

Backlog Management

User stories are prioritized and updated in a backlog for each sprint

Validation & Verification

Requirements are checked and refined during sprints to ensure they meet stakeholder needs

Features

In an agile project, a simple, high-level statement of a requirement

User stories

In an agile project, a set of more refined requirements derived from features

Scenarios

In an agile project, a real-world example of how users will interact with the system

Storyboards

In an agile project, a simple graphic organizer that helps systems analysts visualize the status of a project

Functional decomposition diagram (FDD)

A top-down representation of business functions and processes. Also called a structure chart

Pool

The overall diagram in business process modeling notation (BPMN)

Swim lanes

In a business process diagram, the overall diagram is called a pool, and the designated customer areas are called swim lanes

Unified Modeling Language (UML)

A widely used method of visualizing and documenting software systems design. UML uses object-oriented design concepts, but it is independent of any specific programming language and can be used to describe business processes and requirements generally

SysML

A dialect of UML used for representing requirements (and other things), primarily in Model-Based Systems Engineering (MBSE) applications

Use case diagram

A visual representation of the interaction between users and the information system in UML

Actor

An external entity with a specific role. In a use case diagram, actors model interaction with the system

Sequence diagram

A UML diagram that shows the timing of transactions between objects during system execution

Validation and verification (V&V)

The process of ensuring that system requirements are complete, accurate, consistent, and aligned with stakeholder needs and expectations

Productivity software

Applications such as word processing, spreadsheet, database management, and presentation graphics programs

Personal information manager (PIM)

A tool that helps manage tasks and schedules. Many handheld devices also include this function

Histogram

A standard tool for showing the distribution of questionnaires or sampling results. It takes the form of a vertical bar chart

Traceability

A standard tool for showing the distribution of questionnaires or sampling results. It takes the form of a vertical bar chart