Which of the following must be documented for each derivative classification?

The requirement to document the reasons for classification for each derivative classification is crucial for a few key reasons. First, it provides clarity and justification for why specific information is classified or unclassified, ensuring that the decision is rooted in policy and necessity. This reason serves as a record that can be referenced in the future, allowing for transparency and accountability in the classification process.

Additionally, documenting the reasons helps promote consistent application of classification criteria across different situations and classifiers. This is essential in maintaining an organized and effective classification system, as it assists others in understanding the context and rationale behind the classification decisions. It ensures that any future reviewers can appreciate the specific sensitivities that warranted classification, contributing to proper handling and eventual declassification efforts.

In contrast, while the documentation of dates of classification decisions, names of classifiers, and all previous classified documents has relevance within the broader scope of classification practice, the most critical and foundational necessity lies in clearly outlining the reasons behind classification. This fosters a well-documented and justified framework for derivative classification efforts.