After study and discussion of this question, I now believe that the claimed accuracy of radiometric dating methods is a result of a great misunderstanding of the data, and that the various methods hardly ever agree with each other, and often do not agree with the assumed ages of the rocks in which they are found.Most scientists today believe that life has existed on the earth for billions of years.An examination of sedimentary rocks worldwide shows a striking consistency with the unimaginably massive Flood that wiped out whole environments.It caused massive sedimentary layering and sorting and fossilizing of the creatures buried therein.The potassium-argon method is attractive for dating volcanics since it can be applied to rocks of Pleistocene age and older, thus encompassing important periods of general volcanic activity.However it has been found that dates obtained on whole rocks and on included minerals frequently show gross discordances.The universe is full of naturally occurring radioactive elements.Radioactive atoms are inherently unstable; over time, radioactive "parent atoms" decay into stable "daughter atoms." When molten rock cools, forming what are called igneous rocks, radioactive atoms are trapped inside. By measuring the quantity of unstable atoms left in a rock and comparing it to the quantity of stable daughter atoms in the rock, scientists can estimate the amount of time that has passed since that rock formed.
The determination of the age of such a material would give an old age, and thus account for the anomalies found.
So in order to date most older fossils, scientists look for layers of igneous rock or volcanic ash above and below the fossil.
Scientists date igneous rock using elements that are slow to decay, such as uranium and potassium.
We are told that these methods are accurate to a few percent, and that there are many different methods.
We are told that of all the radiometric dates that are measured, only a few percent are anomalous.