Many of the chronologies constructed before the advent of showed some of the links established by cross-dating to be invalid, so the method has become somewhat discredited.
However, its use is still helpful where recognizable products of dateable manufacture are found in undated contexts with no possibility of using a technique.
A copy of this paper may be found in the Radiocarbon Home Page The radiocarbon age of a sample is obtained by measurement of the residual radioactivity. T (National Institute of Standards and Technology; Gaithersburg, Maryland, USA) Oxalic Acid I (C). The activity of 1890 wood is corrected for radioactive decay to 1950.
This is calculated through careful measurement of the residual activity (per gram C) remaining in a sample whose age is Unknown, compared with the activity present in Modern and Background samples. Thus 1950, is year 0 BP by convention in radiocarbon dating and is deemed to be the 'present'.
The ratio of the activity of sucrose with 0.95 Ox was first measured by Polach at 1.50070.0052 (Polach, 1976b:122).
Another standard, Oxalic Acid II was prepared when stocks of HOx 1 began to dwindle. The ratio of the activity of Oxalic acid II to 1 is 1.29330.001 (the weighted mean) (Mann, 1983). There are other secondary radiocarbon standards, the most common is ANU (Australian National University) sucrose.
These must be accepted on faith in uniformitarian and naturalistic frameworks.
Recent research by a team of creation scientists known as the RATE (arth) group has demonstrated the unreliability of radiometric dating techniques.
Other critics, perhaps more familiar with the data, question certain aspects of the quality of the fossil record and of its dating.
These skeptics do not provide scientific evidence for their views.