For the period around 14,000 to 14,500 years ago, the calibration curve has a specific shape that means that radiocarbon ages in a specific range map to a somewhat wider range of calibrated calendar ages.

The specific calibrated ages reported for the Paisley coprolites in the original 2008 paper, and the refined dates from the expanded radiocarbon program of the 2012 paper, reflect this calibration.

Popular summaries of the Paisley evidence frequently cite a round number — “14,300 years old” or “14,200 years old” — as the age of the oldest coprolites.

These figures are reasonable approximations of the calibrated calendar age range reported in the primary literature, but they should be understood as approximations rather than precise measurements.

The actual calibrated age distribution for the oldest specimens spans a range of years rather than a single point, and the central value of that range is what popular accounts typically report.