Igarashi Revision
Definition
A 2005 Japanese revision of the auricular surface method identifying slower degeneration rates in Japanese populations compared to European reference samples, requiring a correction of approximately 2-5 years when applying European tables to East Asian remains.
- Year
- 2005
- Origin
- Japanese revision of the auricular surface ageing method
- Finding
- Slower degeneration rates in Japanese populations
- Correction magnitude
- Approximately 2 to 5 years
- Applies to
- European reference tables applied to East Asian remains
Common questions
Why do auricular surface degeneration rates differ between population groups at all?+
Degeneration of the sacroiliac joint surface used for age estimation is influenced by biomechanical loading, body size, and possibly genetic and lifestyle factors, which vary across populations. A method calibrated on one reference population can systematically over- or under-age individuals from a different population.
What is the practical consequence of ignoring the Igarashi correction on East Asian remains?+
Applying the uncorrected European tables directly tends to overestimate the chronological age of East Asian individuals, since their joint surfaces degenerate more slowly. Anthropologists apply the Igarashi correction, or use a population-appropriate reference sample when available, to reduce this bias.
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