One source of inaccuracies in radiocarbon dating is contamination.If your sample becomes contaminated with younger, modern material during the sampling process, then it will be invalid. If you sample sediments from the bottom of a lake that has a lot of incoming waters that have ancient radiocarbon in then, then you will derive an anomalously old age.Scientists must understand the sources of error in their dating techniques before calculated ages can be reliably used.
Analytical techniques are very advanced and precise, but they may be inaccurate.
Around Antarctica, the ocean water has a radiocarbon age of around 1300 years, though this varies spatially and may have varied in time as well.
Again, this can affect the accuracy of your results – but the precision remains high.
The precision is effectively the laboratory uncertainty.
The accuracy is how far this probability density curve falls from a reference value.