Principles of Agile Modeling – Agile Modeling (AM) is an iterative and incremental approach to developing just enough models and documents to support the software development process. Rather than creating large upfront models, AM promotes regular communication between developers, customers, and users to build effective models incrementally as they are needed.
Agile Modeling complements agile software development approaches like Scrum, Kanban, and Extreme Programming. It guides how to model and document effectively in an agile context, reducing unnecessary overhead while still capturing critical information.
In this post, I’ll provide an overview of AM – the principles of Agile Modeling, key practices, benefits, and potential challenges. Understanding AM can help teams inspect and adapt their modeling process to become more agile, lightweight, and collaborative. Apply its principles judiciously and AM can maximize the value gained from modeling activities.
Principles of Agile Modelling
AM is guided by a set of 10 core principles that shape its approach to models and documentation:
1. Active Stakeholder Participation – Get hands-on participation from all stakeholders throughout the modeling process – users, managers, developers, etc. Seek their input to ensure the models address their needs.
2. Architecture Envisioning – Focus modeling efforts on envisioning and communicating the overall system architecture with simple conceptual models. Understand the big picture before diving into details.
3. Document Late – Only produce comprehensive documentation like manuals or specifications when it is necessary. Minimize documentation overhead by relying more on conversational knowledge sharing.
4. Executable Specifications – Where possible, use executable specifications like tests, prototypes, and simulations rather than static documents to demonstrate behavior. These artifacts act as living documentation.
5. Iterative – All modeling work should be done iteratively in small chunks, enabling incremental refinement and adaptation. Avoid “big bang” releases.
6. Just Barely Good Enough (JBGE) – Documents and models only need to be good enough for the situation at hand. Over-engineering leads to waste and unused functionality.
7. Model a Little – Do a small amount of modeling to start, focusing on the highest priority needs. Refine the models iteratively as you learn more. Avoid spending too much time upfront.
8. Multiple Models – Use multiple lean models such as UI sketches, workflow diagrams, data models, etc. rather than one large complex model. Different models serve different needs.
9. Prioritised Requirements – Focus first on modeling and delivering the highest priority requirements. Defer lower-priority features until future iterations.
10. Single Source Information – Each important concept, process, or artifact should be found in a single place/document. Avoid duplication and fragmentation.
These principles encourage flexibility, inspection, and adaptation in modeling to build shared knowledge incrementally.
Practices of Agile Modelling
Agile Modelling utilizes many practices to apply its core principles:
- Iterative Modelling – Models are developed incrementally over multiple iterations. The highest priority features or activities are modeled first. Lower priorities wait until the next iteration.
- Just-in-time Modelling – Models are only developed when they are needed to support active development tasks. This avoids waste from models that go unused.
- Active Stakeholder Participation – Engage stakeholders early and often in two-way conversations to clarify details. Avoid only using passive document reviews.
- Prioritised Requirements – Focus on modeling and delivering the highest priority features first based on customer needs. Defer lower-value features to the future.
- Multiple Models – Use multiple lean models such as UI sketches, workflow diagrams, data models, etc. Select the right level of detail for each audience and purpose.
- Model Storming – Quickly brainstorm important concepts and terms with stakeholders using simple sketches and diagrams. Rapidly build initial shared understanding.
- Prototyping – Build simple prototypes to experiment with technical concepts, validate assumptions, and get feedback.
- Testing First – Write executable tests early to define detailed specifications that can be automatically validated. Expand on tests incrementally.
- Document Late – Only produce comprehensive documentation like manuals late in development when necessary.
- Single Source Information – Store all information about a concept in one place/document. Avoid fragmentation and duplication.
- Listen and Clarify – Actively listen to stakeholders and ask clarifying questions to resolve ambiguities early.
- Question Ambiguity – Explicitly highlight unclear assumptions, gaps or inconsistencies to be addressed.
These practices focus modeling efforts on the highest-value activities first. They enable teams to inspect and adapt their understanding while minimizing overhead.
Benefits of Agile Modelling
Applying Agile Modelling practices provides many benefits:
- Reduces the time and cost of modeling because models are developed iteratively and remain lean. Avoid wasted time on unused models.
- Models incrementally evolve making them more flexible and maintainable as new information emerges.
- Active stakeholder collaboration allows models to continuously adapt to changing needs and feedback.
- Focusing on high-priority needs first delivers maximum business value quickly.
- Executable specifications like tests act as living documentation that stays up to date.
- Modeling practices like document late and model storming encourage conversation to build shared understanding.
- Multiple models provide just enough detail for different audiences like developers, users, management, etc.
- Enables improved cross-functional communication between teams like business, development, UX, etc.
- Explicit emphasis on clarity and shared understanding reduces miscommunications.
- Frequently inspecting and adapting models lowers risk and technical debt.
Overall, AM delivers models and documents that provide maximum value with minimal overhead through its streamlined, collaborative approach. Teams receive more useful models in less time.
Challenges of Agile Modelling
While beneficial overall, Agile Modelling does have some potential challenges:
- Requires active stakeholder participation which may not always be possible depending on their availability and commitment.
- Can be difficult for some developers or modelers used to detailed upfront modeling and documentation. It represents a shift in mindset.
- Needs buy-in from the whole team on principles like documenting late, just barely good enough, iterative development, etc.
- Knowledge kept “in people’s heads” through verbal conversations needs to be consciously shared across the team.
- Modeling practices like iterative development require some training for modelers unfamiliar with agile.
- Lack of comprehensive documentation early on means dependencies between models or concepts may not be fully understood.
- Needs management support as agile principles challenge the status quo and modeling assumptions.
- Collaboration-intensive modeling practices demand strong communication skills from both technical and non-technical team members.
- Determining “just enough” modeling for a situation takes practice and judgment skills.
- Tests and prototypes must also be rigorously maintained and funded as key artifacts.
Agile Modelling: Conclusion
Agile Modelling takes an iterative, collaborative approach to developing just enough models and documentation to be maximally useful for software projects. It focuses on active stakeholder participation, iterative development, multiple models, executable specifications, frequent adaptation, and delivery of the highest priority needs first.
While Agile Modeling represents a significant change from traditional modeling, the benefits of improved communication, flexibility, rapid feedback, and reduced modeling waste make it a compelling approach for teams to consider. By applying the principles of agile modeling thoughtfully you should be able to optimize your modeling activities to provide greater overall value.