A data flow diagram illustrates the movement and transformation of data between externals (entities) and processes. The output from one external or process is the input to another. The data flow diagram also illustrates the temporary or permanent repositories (referred to as data stores or terminators) where data is stored within a system or an organization. The data defined should be described in a data dictionary.

A logical data model is used to abstract a 'conceptual data model' by incorporating normalization rules to manage data integrity and relationships. It serves as an abstraction layer that defines the relationships between different data elements, entities, and attributes, focusing on the business concepts and rules that govern the data. This model helps in organizing data to reduce redundancy and improve data integrity, ensuring that the data structure is optimized for both business understanding and database design.
The role and benefits of a logical data model in business analysis are discussed in resources like "What is a Logical Data Model? Definition and Examples" and "The logical data model explained" which detail how logical data models serve as blueprints for structuring enterprise knowledge and ensuring data integrity12.

In the context of managing stakeholder engagement, business analysts (BAs) are particularly vigilant about the risk of scope creep. Scope creep refers to the uncontrolled expansion of project scope without adjustments to time, cost, and resources, which can occur when new requirements are added to the project without proper review. It is a common challenge in project management that can lead to project delays, budget overruns, and can compromise the quality of the final deliverable.
The risk of scope creep is well-documented in business analysis literature, where it is identified as a potential consequence of inadequate stakeholder engagement. Effective stakeholder engagement involves clear communication, setting and managing expectations, and involving stakeholders in the decision-making process to ensure that the project remains aligned with its original objectives12.

The requirements life cycle continues beyond implementation and ends when the solution and the requirements that define it are retired. This marks the conclusion of the requirements ' relevance to the organization and their formal removal from active use.
Exact Extract from BABOK Guide v3 - Section 5: Requirements Life Cycle Management Overview:
"The requirements life cycle ends when a solution component that a requirement traces to is retired."

Business analysts use 'Acceptance and Evaluation Criteria' to measure the quality of requirements. This technique involves setting specific criteria that the requirements must meet to be accepted. These criteria are used to evaluate whether the requirements are well-defined, clear, and meet the necessary standards for successful project outcomes. By establishing these criteria, BAs can ensure that the requirements are aligned with business objectives and can be tested against predefined standards. References: The use of acceptance and evaluation criteria is a common practice in business analysis for ensuring requirement quality and is discussed in various business analysis resources, including the Business Analysis Body of Knowledge (BABOK) guide1.