[en] Materials accounting for special nuclear material in future fuel cycle facilities will draw heavily on sophisticated data-analysis techniques. Decision analysis, which combines elements of estimation theory, decision theory, and systems analysis, can be used to reduce errors caused by subjective data evaluation and to condense large collections of data to a smaller set of more descriptive statistics. The methods and requirements of decision analysis are discussed and illustrated by a conceptual design example of an advanced materials accounting system for a plutonium nitrate-to-oxide conversion facility