It's amazing how consistent measurements can be when one is used to calibrate the other.
All processes in nature vary according to different factors, and we should not expect radioactivity to be different. Scientific Creationism, Green Forest, AR: Master Books, p. Creation Wiki response: The first thing that needs to be noted is that the wording of this claim is not found in Morris' book.
This is Talk Origins' interpretation of his actual comments.
6 Actually such agreement only goes back to about 1000 B. prior to that there starts to be significant disagreement.Furthermore all three other dating methods are used for calibrating at least radiocarbon dating, removing them as independent tests.Reference: Helium Diffusion Rates Support Accelerated Nuclear Decay Reference: Radioisotopes and the Age of the Earth First of all, this only shows that decay rates are not varying right now. In the case of Beta decay the factor is a billion fold.]]
Reference: Billion-fold Acceleration of Radioactivity Demonstrated in Laboratory Reference: Radioactive decay rate depends on chemical environment Reference: Properties of the optical transition in the 229Th nucleus The fine structure constant  is defined as: None of the constants that define the fine structure constant are likely candidates for variability during an accelerated decay event. Furthermore while the fine structure constant affects neutron capture rates, it is not the only factor that does so. Chaffin showed that though the change in well depth is very small (not nonexistent as Talk. Chaffin states that, "even these small variations could allow the U-238 half-life to vary by more than one order of magnitude." (Chaffin. "American Physical Society", The 70th Annual Meeting of the Southeastern Section, November 6-8, 2003, Wilmington, North Carolina) So the Oklo reactor is actually PROOF of accelerated decay. Origin's failed to mention is that the Big Bang theory PREDICTS changes in the fine structure constant.  True, unless there was a mechanism to get rid of the heat.The result is that after evaluating the radiometric dates from 509 locations scattered over Alaska, there is no statistical indication of a trend favoring concordance.Yes, this is based on only 14 samples, but that shows how seldom more than one dating method is used ( or reported ) in radiometric dating.The report containing the charts called Radiometric dates from Alaska - a 1975 compilation  is simply a chart of data with no interpretation beyond the date calculations.Now 62% of the locations had only one date and so there was nothing to compare the dates to.Accelerated decay is now associated with two Biblical events, Creation and the Flood, and both events are literally acts of God.