Which characteristic describes a reference systems engineering model?

A reference systems engineering model is characterized by its extensibility, scalability, and ability to be tailored to fit the specific needs of different projects. This flexibility allows stakeholders to adapt the model to a variety of contexts and requirements, enhancing its usefulness across different systems engineering scenarios.

Extensibility refers to the model's capability to incorporate additional features or components without losing its core functionality. Scalability indicates that the model can effectively function for projects of varying sizes and complexities, whether small or large. Tailoring means that users can modify the model to align with their specific processes, methodologies, or organizational needs, ensuring that it remains relevant in diverse environments.

In contrast, a model that is largely unchangeable would be less effective in accommodating different project requirements and evolving industry practices. A costly and complex model may deter adoption and implementation, and a model limited to small projects would undermine its value in handling the broader spectrum of systems engineering challenges. Thus, the characteristic that best describes a reference systems engineering model is its extensibility, scalability, and tailorability.