Tailoring

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Project-level tailoring adapts ISO/IEC/IEEE 15288 processes to specific contexts, balancing rigor, risk, and flexibility. It is dynamic, evidence-based, and aligned with project planning. Success depends on stakeholder collaboration, documentation, and continuous review. Good practices emphasize fact-based decisions, tool integration, and adaptability, while avoiding over-engineering, uniformity, and neglecting stakeholder engagement.

Fundamental Concepts

While organizations provide governance and overarching frameworks (see articles Adapting the Life Cycle Model and Adapting the Development Approach), tailoring can be needed on the project level. ISO/IEC/IEEE 15288, along with related elaboration standards (ISO/IEC/IEEE 24748 series), defines a comprehensive set of life cycle processes that can be applied to projects of any size and complexity. However, no project can adopt these processes “off the shelf.” They should be tailored to the specific project environment, stakeholders, and risks.

The Role of Tailoring

Tailoring at the project level involves adjusting life cycle processes to ensure that they meet the unique requirements of the project. These adjustments scale the rigor of processes to a level appropriate to project risk, complexity, and constraints. For example:

• A project with tight budgets and low tolerance for failure can benefit more rigorous verification and validation activities.
• A small project with low complexity and high trust among stakeholders may streamline certain formal reviews to save cost and time.

Tailoring is not a one-time activity, but a dynamic process. As risks and circumstances evolve, tailoring should be revisited throughout the life cycle. As shown in Figure 1, it balances the dangers of two extremes:

Too little rigor, which raises the risk of technical issues, schedule slips, or cost overruns.

Too much rigor, which introduces unnecessary process overhead, reduces flexibility, and inflates cost.

PLACE FIGURE HERE

Figure 1: Tailoring requires balance between risk and process. INCOSE SEH original figure created by Krueger adapted from Salter (2003). Used with permission.

Project Context Factors

According to PMI Scaling Factors, several factors shape how tailoring decisions are made:

1. Team size
2. Geographic distribution
3. Organizational distribution
4. Skill availability
5. Compliance
6. Domain complexity
7. Solution complexity

Other factors that can be considered are:

1. Stakeholder landscape
2. Budget and schedule
3. Risk tolerance
4. Criticality of the project (safety, mission, etc.)

In all cases, tailoring seeks to ensure that processes are fit for purpose, supporting the project’s goals while managing risk at an acceptable level.

Concurrency, Iteration, and Recursion

As described in article Process Concurrency, Iteration, and Recursion, life cycle processes are applied in ways that are concurrent, iterative, and recursive. For instance, requirements definition, architecture definition, and verification may occur simultaneously and in multiple cycles as knowledge evolves. The processes are recursively applied throughout the system structure. This recursive application ensures coherence across project activities and maintains traceability of decisions.

Good Practices

Project success depends on disciplined tailoring, transparent agreements, and effective use of tools and methods. Several practices have proven especially valuable.

Fact-Based Tailoring

Tailoring decisions should not rely on intuition alone. Instead, they should be based on facts, evidence, and risk assessment. Independent review or approval can help avoid bias. Using structured Decision Management processes to document alternatives, trade-offs, and rationales creates a traceable record that supports accountability.

Documenting and Validating Assumptions and Rationale

Every tailoring choice should be explicitly justified and recorded. For example, if a project reduces the number of formal design reviews, it should document why (e.g., high team cohesion, proven system element maturity). This documentation ensures that later stakeholders (especially during audits or project transitions) understand the reasoning behind earlier decisions.

Collaboration with Stakeholders

Projects rarely operate in isolation. Tailoring works best when all relevant stakeholders (e.g., acquirers, suppliers, and regulators) are involved in defining and approving the tailoring approach. Collaborative agreements build trust and reduce disputes later in the life cycle. As trust grows or project risks or complexity reduces[GR10] , projects can simplify some process activities; conversely, when risks rise, additional rigor can be introduced.

Integration with Project Planning

Tailoring should be conducted in parallel with project planning. Decisions on scope, schedule, budget, milestones, and resource allocation are tightly linked to the processes chosen or how they are applied. For example, aggressive schedules can require automated testing tools to accelerate verification, while budget constraints may limit the number of prototypes built. Alignment ensures that plans are realistic and processes are executable.

Dynamic Assessment and Control

Tailoring is not static. Throughout the project, effectiveness and efficiency of tailoring should be continuously assessed and, if necessary, controlled (see article Project Assessment and Control) in response to changing risks, stakeholder feedback, or external conditions. For example, if a project experiences unanticipated technical problems, additional design reviews can be added. Conversely, if risks decrease, some formalities can be reduced to save time.

Methods and Tools at Project Level

Though ISO/IEC/IEEE 15288 does not prescribe specific tools, projects benefit from structured selection and disciplined use of methods and tools. Key considerations include:

• Purpose-driven selection: Tools should directly support tailored processes; process comes before tool.
• Connectivity: Tools should integrate with other tools in use, ensuring smooth data flow across project functions.
• Training requirements: Staff need adequate preparation to use tools effectively.
• Engineer judgment: Tools are aids, not substitutes for critical thinking.
• Data availability: Tool selection should consider what data is needed and whether that data can easily be obtained and verified.

Practical Applications of Life Cycle Processes

According to ISO/IEC/IEEE 24748-2, ISO/IEC/IEEE 15288 processes can be applied in at least four practical ways:

• to establish agreements with organizational entities external and internal to the project to acquire or supply a product or service (agreement processes);
• to establish the organization’s capability to acquire and supply products or services through the initiation, support and control of projects (organizational project-enabling processes);
• to establish and evolve project plans, to execute the project plans, to assess actual achievement and progress against the plans and to control execution of the project through to fulfilment (technical management processes);
• to contribute to the satisfaction of technical objectives for one or more life cycle stages (technical processes).

By focusing on these purposes, projects ensure that process tailoring delivers tangible value rather than administrative burden.

Challenges

Even with clear principles and good practices, projects face substantial challenges when tailoring and applying life cycle processes.

Common Tailoring Traps

Projects often fall into predictable traps, including:

• Reusing baselines blindly: Borrowing a tailored process from another project without revisiting assumptions.
• Over-engineering: Applying all processes “just to be safe,” leading to unnecessary costs and delays.
• Assuming uniformity: Believing that the same set of risks or controls applies across all projects.
• Failing to engage stakeholders: Excluding key voices, which leads to lack of buy-in and increased risk of conflict.

Disciplined decision-making and continuous review can facilitate avoiding these traps.

Complexity of Multi-Stakeholder Projects

Projects often involve multiple stakeholders with different priorities and policies. Achieving alignment requires:

• Establishing consistent processes across parties.
• Negotiating agreements that balance competing needs.
• Using ISO/IEC/IEEE 15288 as a shared reference framework.
• Still, differences in culture, terminology, and expectations remain significant hurdles.

Tool and Method Pitfalls

On many cases, tools pose challenges:

• Lack of integration between tools creates silos and rework.
• Security and data management issues complicate tool lifecycle.
• High training requirements can strain limited project resources.
• Over-reliance on tools risks diminishing engineers’ independent judgment.

Data availability and verification

• “Garbage in, Garbage out”.

Maintaining Stakeholder Commitment

Tailoring of processes  benefits from strong stakeholder commitment. If stakeholders view processes as excessive overhead, they can resist compliance. Conversely, if they perceive insufficient rigor, they may lose confidence in the project’s ability to deliver. Active communication and visible leadership support are essential to maintain alignment.

Conclusion

At the project level, tailoring systems engineering life cycle processes is both a necessity and an opportunity. Standards such as ISO/IEC/IEEE 15288 provide a comprehensive framework, but projects should adapt these processes to their specific context, risks, and stakeholder environment.

Good practices include fact-based tailoring, documentation of rationale, stakeholder collaboration, integration with project planning, dynamic monitoring, and thoughtful tool use. By applying processes in ways that are practical and purpose-driven, projects can increase efficiency, reduce risk, and maintain stakeholder confidence.

Nevertheless, challenges remain. Projects should avoid common tailoring traps, balance rigor with agility, manage multi-stakeholder complexity, and ensure that tools support rather than dominate decision-making. Above all, continuous adaptation and transparent communication can help ensure that processes remain aligned with project needs.

In the end, project-level tailoring is not about minimizing process effort or maximizing bureaucracy. It is about applying the right processes, at the right level of rigor, at the right time to deliver systems that meet stakeholder needs effectively and efficiently.

References

Works Cited

ISO/IEC/IEEE. 2023. Systems and software engineering — System life cycle processes. Geneva, Switzerland: International Organization for Standardization (ISO), International Electrotechnical Commission (IEC), and Institute of Electrical and Electronics Engineers (IEEE). ISO/IEC/IEEE 15288:2023.

ISO/IEC/IEEE. 2024. Systems and software engineering — Life cycle management — Part 2: Guidelines for the application of ISO/IEC/IEEE 15288 (system life cycle processes). Geneva, Switzerland: International Organization for Standardization (ISO), International Electrotechnical Commission (IEC), and Institute of Electrical and Electronics Engineers (IEEE). ISO/IEC/IEEE 24748-2:2024.

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