A relative dating method based on the fact that artefact types change through time in frequency as a result of new technologies, styles, and available construction materials. The frequency of artefact types in a stratum can be compared to known frequency changes previously recorded for an ancient culture. In this way, the stratum can be dated relative to other strata or sites. When a seriation sequence has been cross-calibrated with reliable chronometric dating methods, it can be considered a calibrated relative technique.