Your new material may aggregate pieces of information that are not individually classified. What is this classification concept called?

The correct answer is classification by compilation. This classification concept pertains to the process of combining unclassified information to create a new piece of material that may require classification due to the sensitive nature of the aggregated content, even if the individual pieces of information themselves are not classified. When different data points are brought together, the risk of revealing sensitive or classified information increases, thus necessitating a classification decision based on the new, compiled context.

This concept is particularly important in derivative classification, where individuals must recognize that not only the original sources but also the manner and context in which information is compiled may affect classification requirements. Understanding classification by compilation helps ensure that sensitive data is appropriately managed and protected, adhering to legal and security guidelines.

The other options, while relevant to classification practices, do not pertain specifically to the aggregation of unclassified pieces of information into a potentially classified context. Thus, they do not accurately represent the concept in question.