> In your experience, to have over 400 samples say
> the same thing between two tests taken 10yrs
> apart, not to mention other RCD tests done which
> all fall in the same range-how much of this
> matters as a whole to the credibility of these
> tests? Meaning, what is the likelihood of all the
> tests always being wrong the same way no matter
> who is doing it or when?
The reported results are powerful enough to lead us to quibble--and all scientists will quibble away with very little provocation. The most complete way to start the process is to go back to the beginning and review.
Before any data is gathered, one must build and calibrate an instrument. To assure maximum sensitivity, one must target a specific time period and desired resolution. As one deviates from those targets, one might want to scale deviations to fit a normal curve. Meaningful deviations from the target might then be limited to little more than two standard deviations from the target. Calculated values beyond two standard deviations would tend to jump around, since the sensitivity is increasingly reduced. They might even be regarded as outliers and discarded.
To make the instrument more useful, one might design and calibrate multiple scales with different targets--but the underlying sensitivity of the C14 calculation limits the range of useful targets, and changes the resolution capabilities around each target. No matter how objective the intent, the instrument will always be designed with (literally) built in biases.
Just in this very first step, there is reason for dispute, the greater the measured discrepancy. There is also a basis for dispute in the selection of 1) target dates: do we really want to choose an "established" target, like 2500 BC? and 2) scaling choices: do we really need to scale with a normal curve when we're only interested in one half of the curve? Maybe some other scale?
Only the first step in our quibbling, and we can already see problems.
When we begin to apply all possible quibbles, we won't be sure of anything any more.
Start over? Of course not. These results are very interesting and suggestive. But they could be wrong.
> > Short of that, your summary certainly is
> > provocative, but in need of further
> > clarification.
> Is there something that could be done, or wasn't
> done, to these samples that would make them
> 20,000yrs old instead of 5,000?
If the instrument could be recalibrated to target much later dates, and the sampling procedure adjusted to the oldest possible obtainable samples, a more diverse range of dates with no clear mean might permit the possibility of 20,000 years--but such data might not be very reliable.