Approaches to System Development

Approaches to System Development

Learning Objectives

• Predictive vs. Adaptive SDLC:

  • Compare assumptions and uses of predictive and adaptive system development life cycles (SDLC).

  • Predictive SDLC (e.g., Waterfall): Assumes comprehensive planning is possible upfront.

  • Adaptive SDLC (e.g., Agile): Employs iterative models to accommodate changing needs.

• System Development Methodology:

  • Explain the components of a system development methodology, including the SDLC, models, tools, and techniques.

  • A methodology provides a structured approach with specific tools and techniques.

• Agile Development:

  • Describe the key features of Agile development.

  • Agile emphasizes flexibility, collaboration, and delivering working software quickly.

The System Development Life Cycle (SDLC)

• Two general approaches:

  • Predictive Approach:

  • Also known as the Waterfall model.

  • Assumes project planning can be done extensively in advance.

  • Assumes the information system can be developed according to the detailed plan.

  • Relies on a thorough understanding of requirements and stable technology.

  • Suitable when requirements are well understood and/or technical risk is low.

  • Change control is formal and rigorous.

  • Adaptive Approach:

  • Employs an iterative model.

  • Assumes the project must be flexible and adapt to evolving needs and discoveries.

  • Requirements are expected to change, and learning occurs throughout the project.

  • Suitable when requirements and needs are uncertain and/or technical risk is high.

  • Change is embraced, and iterations allow for continuous refinement.

• Most projects fall between purely predictive and purely adaptive approaches;

  • A tailored hybrid approach is often best, blending elements of both predictive and adaptive methods to suit specific project needs.

Systems Development Methodology

• A formalized approach to implementing the Systems Development Life Cycle (SDLC).

• Includes specific steps, techniques, tools, and documentation standards.

• Main types:

  • Waterfall Development

  • Traditional, sequential approach.

  • V-Model

  • Extension of Waterfall, emphasizing testing.

  • Parallel Development

  • Sub-parts of the system developed simultaneously.

  • Iterative Development

  • Develops the system in repeated cycles.

  • Rapid Application Development (RAD)

  • Focuses on speed and user involvement.

  • System Prototyping

    • Creation of preliminary models.

  • Throwaway Prototyping

    • Prototypes discarded after use.

  • Dynamic Systems Development Method (DSDM)

    • Agile approach focusing on user needs.

  • Agile Development

  • Emphasizes flexibility and collaboration.

  • Scrum

    • Iterative, team-based approach.

  • Extreme Programming

    • Focuses on code quality and testing.

Traditional Predictive SDLC

• Earlier approach based on engineering principles.

• Characterized by detailed upfront planning and sequential execution.

• Typically has sequential phases:

  • Phases are related groups of development activities (e.g., planning, analysis, design, implementation, and deployment).

  • Planning: Define project scope and objectives.

  • Analysis: Gather and analyze requirements.

  • Design: Create system architecture and specifications.

  • Implementation: Develop the system.

  • Testing: Verify system functionality.

  • Deployment: Release the system to users.

• Waterfall model:

  • An SDLC that assumes phases can be completed sequentially with no overlap or iteration.

  • Once a phase is completed, you proceed to the next phase without going back.

  • Relies on comprehensive documentation at each phase.

Traditional IS Development Phases

• (The transcript refers to a diagram of Traditional IS Development Phases here.)

Waterfall Predictive SDLC

• (The transcript refers to a diagram of Waterfall Predictive SDLC here.)

Modified Waterfall with Overlapping Phases

• Offers more flexibility but still assumes predictive planning and sequential phases.

• Some overlap between phases to allow feedback and adjustments.

Newer Adaptive SDLC

• Emerged in response to complex requirements and uncertain technological environments.

• Values flexibility, collaboration, and continuous improvement.

• Always includes iterations where some design and implementation are done from the beginning.

• Each iteration involves planning, design, implementation, and testing.

• Some developers consider it the only viable way to develop information systems.

• Promotes responding to change over following a rigid plan.

• Some IS managers are skeptical due to the apparent lack of an overall plan.

• Requires strong communication and coordination.

Adaptive Approaches

• Incremental development:

  • Completes portions of the system in small increments and integrates them as the project progresses.

  • Each increment provides a working subset of the system.

  • Sometimes considered “growing” a system.

  • Allows for early and frequent feedback.

• Walking Skeleton:

  • The complete system structure is built first but with bare-bones functionality.

  • Essential framework is established early.

  • Functionality is added incrementally.

Generic Adaptive Approach

• Six Core Processes that go across iterations.

• Multiple iterations as required.

Methodologies, Models, Tools, and Techniques

• A Methodology includes a collection of techniques that are used to complete activities and tasks, including modeling, for every aspect of the project.

Methodologies, Models, Tools, and Techniques(Cont.)

• Tools:

  • Software applications that assist developers in creating models or other components required for a project.

  • Examples: Visio, Figma, MySQL, Project, Word, etc.

Methodologies, Models, Tools, and Techniques(Cont.)

• Technique:

  • A collection of guidelines that help an analyst complete an activity or task.

  • Learning techniques is the key to expertise in a field.

Agile Development

• A guiding philosophy and set of guidelines for developing information systems in an unknown, rapidly changing environment.

• Emphasizes collaboration, iterative development, and responding to change.

• Chaordic:

  • A term for adaptive projects, describing them as chaotic yet ordered.

Agile Development Values

• From the “Manifesto for Agile Software Development”:

  • Value responding to change over following a plan.

  • Value individuals and interactions over processes and tools.

  • Value working software over comprehensive documentation.

  • Value customer collaboration over contract negotiation.

Agile Modeling Principles

• Agile Modeling (AM) – 12 Principles

• A philosophy – build only necessary models that are useful and at the right level of detail.

• Focus is on creating models that add value to the project.

Agile Principles

• Develop software as the primary goal, avoiding distraction by excessive documentation or models.

• Enable the next effort as your secondary goal, being aware of next step versions or revisions.

• Minimize your modeling activity.

• Only build what helps move the project forward.

• Embrace change and change incrementally.

• Take small steps that keep you on track and that can be reversed if necessary.

Agile Principles (Cont.)

• Model with a purpose; model to understand and communicate.

• Build multiple models.

• Look at problems from different perspectives.

• Build high-quality models and get feedback.

• Focus on content rather than representation; informal hand-drawn models are sometimes okay.

• Always focus on stakeholder needs.

Agile Principles (Cont.)

• Learn from each other with open communication.

• Know your models and how to use them.

• Adapt to specific project needs.

• Maximize stakeholder ROI.

Agile Approaches

• Unified Process (UP)

  • Iterative and incremental framework.

• Extreme Programming (XP)

  • Focuses on code quality and customer involvement.

• Scrum

  • Iterative, team-based approach.

SCRUM

• Intense effort involving the entire team for a defined period.

• Project is broken down into short iterations called sprints.

• Product backlog:

  • Prioritized list of user requirements.

• Product owner:

  • The client stakeholder who controls the backlog.

• Scrum master:

  • Scrum project manager.

• Scrum sprint:

  • A time-controlled mini-project to implement part of the system.

SCRUM Process Description

• (The transcript refers to a diagram of the SCRUM process here.)

SCRUM Components

• Product owner

• Product backlog

• Sprint planning meeting

• Scrum master

• Scrum team

• Sprint backlog

• 30-day Scrum sprint

• Incremental software result

• Daily scrum

Scrum Practices

• Scope of each sprint is frozen (but can be reduced if necessary).

• Time period is kept constant.

• Daily Scrum meeting:

  • What have you done since the last daily Scrum (during the last 24 hours)?

  • What will you do by the next daily Scrum?

  • What kept you or is keeping you from completing your work?

Summary

• This chapter covers approaches to system development in more detail.

• There are two approaches to the SDLC: Predictive and Adaptive.

• A predictive SDLC, also known as the waterfall model, is used when it is possible to plan the project completely in advance.

• An Adaptive SDLC, which uses