Radiometric dating percent error
He is very good at showing the many ways that things can go wrong; he has not shown that things normally go wrong.
Woodmorappe's main theme, minus the diplomatic wording, is that geologists are cheating like so many schoolboys to make their dates come out right.In a number of instances, more than you might imagine, dates are further corroborated by methods that have nothing to do with radioactivity.Thus, the big, statistical picture painted by radiometric dating is excellent.(Matson, 1993, p.1) Either we have a worldwide conspiracy among geologists, which no sane person believes, or else the numerous radiometric dates were consistent enough to allow that kind of close agreement. Dalrymple, an expert in radiometric dating with lots of hands-on experience, puts the percentage of bad dates at only 5-10 percent.Thus, we clear away the first illusion spun by creationism, namely that most of the dates are bad, that the radiometric picture is totally chaotic.Upon being presented with claims that radiometric dating is totally erroneous, a question naturally arises: If radiometric geochronology is half as bad as Woodmorappe's list suggests, then how in the world did geologists ever arrive at a tight consensus for the official dates?Look at the various radiometric tables in use over the last 20 years or so and you will find, at least for the fossil-bearing strata, a remarkably tight agreement. Did the geochronologists throw darts to determine the accepted dates?The interpretation that the data represent a 34-billion-year isochron is solely Woodmorappe's  and is patently wrong.(Dalrymple, 1984, pp.78-79) Whatever the reasons may be for the scatter, the fact remains that these data were clearly a "discard" case.An eye-opener awaits anyone who closely examines Woodmorappe's list of bad dates. The results make the method stronger, either by advising us to avoid certain minerals under certain conditions or by building our confidence in applying it to new materials or situations. That is, they were rejected because of internal indicators (such as a bad isochron) rather than on the basis of the final date produced. All of the dates lack the investigator's personal, detailed interpretation. Again, one must demonstrate that a bad date would have been counted as a good date had it not been contradicted by outside data.Some of the dates involved minerals that even Woodmorappe admits are unreliable. If the radiometric method is to be indicted, it must be indicted by dates which were counted as good but shown, by other means, to be bad. Properly interpreted, a number of gross "errors" listed in Woodmorappe's table simply vanish!