In a separate article (Radiometric dating), we sketched in some technical detail how these dates are calculated using radiometric dating techniques.
As we pointed out in these two articles, radiometric dates are based on known rates of radioactivity, a phenomenon that is rooted in fundamental laws of physics and follows simple mathematical formulas.
Radiometric dating is self-checking, because the data (after certain preliminary calculations are made) are fitted to a straight line (an "isochron") by means of standard linear regression methods of statistics.
The slope of the line determines the date, and the closeness of fit is a measure of the statistical reliability of the resulting date.
Only rarely does a creationist actually find an incorrect radiometric result (Austin 1996; Rugg and Austin 1998) that has not already been revealed and discussed in the scientific literature.
The creationist approach of focusing on examples where radiometric dating yields incorrect results is a curious one for two reasons.
Scientists date igneous rock using elements that are slow to decay, such as uranium and potassium.
Other creationists have focused on instances in which radiometric dating seems to yield incorrect results.
In most instances, these efforts are flawed because the authors have misunderstood or misrepresented the data they attempt to analyze (for example, Woodmorappe 1979; Morris HM 1985; Morris JD 1994).
Fossils are collected along with rocks that occur from the same strata.
These samples are carefully cataloged and analyzed with a mass spectrometer.