Eren, Metin I.Dominguez-Rodrigo, ManuelKuhn, Steven L.Adler, Daniel S.Le, IanBar-Yosef, Ofer2025-12-182025-12-180305-4403ORCID:/0000-0001-6751-0898/work/219177792https://hdl.handle.net/1885/733796581Observations pertaining to particular stages of the lithic chaîne opératoire, or reconstructions of the entire operational sequence at a particular site, can be used to develop a detailed understanding of past human cognitive capabilities, technological sophistication, mobility, and land use. The "reduction sequence" is a specific stage of the chaîne opératoire that many archaeologists have attempted to measure. Many of these attempts fail to recognize that "reduction" is a three-dimensional process, and thus should be measured with an appropriate three-dimensional unit: Volume. This paper presents a new methodology for measuring and defining reduction in unifacial stone tools that reconstructs the original volume of a modified blank, allowing a realistic percentage of volume loss to be calculated. This new method is fast, precise, and very accurate.The authors would like to thank the following people and institutions for support, criticisms, laboratory space, and funding: Dr. Mustafa Eren, Mrs. Kathleen Eren, Ms. Nimet Eren, Dr. Brian G. Redmond, Mr. Mark Kollecker, Ms. Mary Prendergast, Dr. Emily Moss, Mr. Aaron Greenspan, Mr. Alex Potapov, Ms. Andrea Leahy, the Stone Age Laboratory at Harvard University's Peabody Museum of Archaeology and Ethnology, the Department of Archaeology at the Cleveland Museum of Natural History, and the Cleveland Archaeological Society (a chapter of the Archaeological Institute of America). The four anonymous reviewers' comments were extremely helpful, and we sincerely thank them for their thorough and constructive comments. Eren devised the method and derived the mathematical proof, and Eren and Dominguez-Rodrigo conducted the experimental analysis for this study.12enChaîne opératoireExperimental archaeologyLithic technologyReduction sequenceUnifacial stone tools200510.1016/j.jas.2005.03.00320544446348