Which aspect is crucial for controlling scope creep?

The emphasis on careful documentation and project management is essential for controlling scope creep because it ensures that changes to the project scope are systematically tracked, evaluated, and managed. Comprehensive documentation provides a clear record of the project's original objectives, requirements, and agreed-upon scope. This clarity helps project managers identify and evaluate any proposed changes against the established goals and scope.

When project management practices are robust, it allows teams to assess the impact of potential changes, facilitates communication among stakeholders, and aids in making well-informed decisions regarding whether to incorporate changes. Effective project management practices, including maintaining a change control process, further help in monitoring project progress and ensuring alignment with the original goals, minimizing the risk of scope creep.

The other options, while relevant to project management, do not directly address the specific mechanism of controlling scope creep as effectively. Reactive project changes may lead to disorganization and uncertainty; involving stakeholders at every decision point can complicate decision-making rather than streamline it; and limiting team size does not inherently control changes to the project scope, but rather influences communication dynamics. Thus, careful documentation and project management stand out as the most critical elements in managing scope creep effectively.