Compare methods

	Frequency Seriation	Contextual Seriation
Field	Archaeology	Archaeology
Family	Process / pipeline	Process / pipeline
Year of origin	1962	1899
Originator	Leslie Spier; James A. Ford (developed from W. M. F. Petrie's sequence dating)	W. M. F. Petrie (sequence dating); formalized as occurrence seriation by mid-20th-century quantitative archaeologists
Type	Relative-chronology ordering of assemblages by type proportions	Relative-chronology ordering of units by presence-absence of types
Seminal source	Lyman, R. L., & O'Brien, M. J. (2006). Measuring Time with Artifacts: A History of Methods in American Archaeology. University of Nebraska Press. ISBN: 9780803280526	Lyman, R. L., & O'Brien, M. J. (2006). Measuring Time with Artifacts: A History of Methods in American Archaeology. University of Nebraska Press. ISBN: 9780803280526
Aliases	Frequency Seriation Dating, Battleship-Curve Seriation, Proportional Seriation	Occurrence Seriation, Sequence Dating, Incidence Seriation
Related	3	3
Summary	Frequency seriation is a relative-dating technique that orders archaeological assemblages in time by the changing proportions of the artifact types they contain. Its premise is that any cultural type is introduced, gradually becomes popular, peaks, and then declines, so that the relative frequency of a type traces a single rise-and-fall curve through time. By rearranging the rows of a type-by-assemblage abundance table until every type's frequency forms one continuous unimodal sequence, the analyst recovers an ordering interpreted as chronological. Drawn as horizontal bars, these curves take the lens or 'battleship' shape that gives the method its popular name. Frequency seriation grew out of W. M. F. Petrie's sequence dating and was formalized for proportional data by mid-twentieth-century Americanists such as James A. Ford, becoming a backbone of culture-historical chronology before absolute dating was widely available.	Contextual seriation, also called occurrence or sequence seriation, is a relative-dating method that orders discrete archaeological units — typically graves or closed deposits — using only the presence or absence of artifact types within them. Its logic is the lifespan assumption: each type is introduced, used continuously for some span, and then disappears, so the contexts in which a type occurs should form an unbroken stretch of the sequence. By permuting the rows and columns of a presence-absence matrix until every type's occurrences cluster into a single contiguous block, the analyst recovers a one-dimensional ordering interpreted as time. The technique originates with W. M. F. Petrie's sequence dating of Egyptian predynastic graves and remains a standard tool for chronology where only incidence data, not abundances, are available.