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Interlaboratory Comparisons: Lessons Learned

Published online by Cambridge University Press:  18 July 2016

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Abstract

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Interlaboratory comparisons have been widely used in analytical chemistry and radiochemistry as an important part of ongoing quality assurance programs. The 14C community has been no exception in this respect, and in just under 20 years, there have been a number of significant and very extensive interlaboratory trials organized by individual laboratories and the International Atomic Energy Agency (IAEA) to the benefit of the 14C community (both labs and users) (Otlet et al. 1980; ISG 1982; Scott et al. 1990; Rozanski et al. 1992; Scott et al. 1992; Gulliksen and Scott 1995). The comparisons have varied widely in terms of sample type and preparation, but all have had as their primary goal the investigation of the comparability of results produced under possibly quite different laboratory protocols. As techniques have been developed and new labs formed, the reference materials created as a result of the intercomparisons have presented an opportunity for checking procedures and results. Users have been reassured by the existence of regular comparisons as one sign of the concern that laboratories have to ensure highest quality results, but also confused about how to make use of the results from past exercises in the interpretation of sets of dates from many laboratories. The laboratories have also learned valuable lessons from participation in such studies. These have included identification of systematic offsets and additional sources of variation and in studies which have used realistic samples requiring pretreatment, chemical synthesis and counting, it has been possible to identify the stage at which such problems have arisen and to quantify the relative contributions to the overall variation. In this paper, we will briefly review the comparisons so far, draw some conclusions from their findings, and make proposals for the future organization of intercomparisons.

Type
Part 1: Methods
Copyright
Copyright © The American Journal of Science 

References

Gulliksen, S. and Scott, E. M. 1995 Report of the TIRI workshop. In Cook, G. T., Harkness, D. D., Miller, B. F. and Scott, E. M., eds., Proceedings of the 15th International 14C Conference. Radiocarbon 37(2): 820822.Google Scholar
ISG 1982 An inter-laboratory comparison of radiocarbon measurements in tree-rings. Nature 198: 619623.Google Scholar
ISG 1983 An international tree-ring replicate study. In Waterbolk, H. T. and Mook, W. G., eds., 14C and Archaeology. PACT 8: 123233.Google Scholar
Long, A. and Kalin, R. M. 1990 A suggested quality assurance protocol for radiocarbon dating laboratories. Radiocarbon 32(3): 329334.Google Scholar
Otlet, R. L., Walker, A. J., Hewson, A. D. and Burleigh, R. 1980 14C interlaboratory comparison in the UK: Experiment design, preparation and preliminary results. In Stuiver, M. and Kra, R. S., eds., Proceedings of 10th International 14C conference. Radiocarbon 22(3): 936947.Google Scholar
Rozanski, K., Stichler, W., Gonfiantini, R., Scott, E. M., Beukens, R. P., Kromer, B. and van der Plicht, J. 1992 The IAEA 14C intercomparison exercise 1990. In Long, A. and Kra, R. S., eds., Proceedings of the 14th International 14C Conference. Radiocarbon 34(3): 506519.Google Scholar
Scott, E. M., Aitchison, T. C., Harkness, D. D., Cook, G. T. and Baxter, M. S. 1990 An overview of all three stages of the international radiocarbon intercomparison. Radiocarbon 32(3): 309319.Google Scholar
Scott, E. M., Harkness, D. D., Miller, B. F., Cook, G. T. and Baxter, M. S. 1992 Announcement of a further international intercomparison exercise. In Long, A. and Kra, R. S., eds., Proceedings of the 14th International 14C Conference. Radiocarbon 34(3): 528532.Google Scholar
Scott, E. M., Long, A. and Kra, R. S., eds. 1990 Proceedings of the International Workshop on Intercomparison of Radiocarbon Laboratories. Radiocarbon 32(3): 253397.Google Scholar
Wilson, S. R. and Ward, G. K. 1981 Evaluation and clustering of radiocarbon age determinations: Procedures and paradigms. Archaeometry 23(1): 1939.Google Scholar