In particular I am interested in whether it is more closely related to 'precision' or 'accuracy'. So a somewhat mathematical description might be appropriate. For example the word 'fidelity' occurs at 23:54 in the BICEP2 press release video, where it is emphasised as being different to sensitivity. Which term, 'precision' or 'accuracy', is more closely related to the concept of 'fidelity'?
1) Precision
2) Accuracy