Hi Mark,

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Isn't the reference date before present 'BP' taken as 1950, so minus 3990 years would be 2041 BC as there is no year 0 with one year from AD 1 to 1 BC?
Isn't the date 2670 BC plus or minus 108 years from your calculation.

Radiocarbon years (BP) do not directly correspond to calendar years (cal BP, cal BC/AD) due to atmospheric fluctuations of 14C. To convert radiocarbon years into calendar years a calibration is required using calibration curve (I used Calib for calibration).

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In the 2013 Oxford paper I think I recall reading that an individual sample could only be expected to give a date of plus or minus 100 years, but that a large number of samples would give a much more precise date from statistics.

I became interested in the question whether the radiocarbon method is accurate enough to confidently detect a discrepancy of 200 years for a period with the age of more than 4,500 years (200/4500 = ~ 4%).

Two tables (Table S3, Table S4) of inter-laboratory comparisons (Oxford, Vienna, Saclay) have been published in the Appendix to "Radiocarbon-Based Chronolgy for Dynastic Egypt" (2010).
The tables show that the differences in laboratory results can reach up to 80 radiocarbon years (80/3200 = 2.5%), but for a large set they must compensate each other.

It can be seen that for no one sample belonging to the Old Kingdom, which we are particularly interested in, such an inter-laboratory comparison has not been given. There is no mention of inter-laboratory comparisons in the Appendix to "An absolute chronology for early Egypt using radiocarbon dating and Bayesian statistical modelling" at all.

Thus, it turns out that I can neither check the correctness of the Oxford data for the Old and Early Kingdom, nor estimate the inter-laboratory error for these periods.

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The re-evaluation of this sample would be a useful academic exercise to assess the quality of radiocarbon analysis in 1970 by comparing the old raw data to new raw data taking into account the sample is now 50 years old if it was actually done in 1970. The paper by Edwards did not actually state when it was done.
It seems the Oxford study would be improved by looking at samples from the Fourth Dynasty, so I think there are two reasons to re-evaluate this sample.

I don’t understand for what reason since 2010 until now radiocarbonists have not conducted a study dating a large number of samples for the Old Kingdom (given the fact that the 2001 large-scale study revealed a discrepancy between the results and expectations for this period).

Alex.