Point estimates of calibrated radiocarbon dates

This function implements a number of methods for deriving a single point estimate of calendar age from calibrated radiocarbon dates. Note that none of these methods produce a good estimate (Michczyński 2007) , and should only be used as a last resort if the probability distribution function or an interval estimate is not appropriate, in which case method = "mode" (the default) is recommended.

Usage

cal_point(
  x,
  method = c("mode", "median", "mean", "local_mode", "central"),
  interval = 0.954
)

Arguments

x

cal object. A vector of calibrated radiocarbon dates.

method

Character. Method of estimation:

"mode" (default)

age corresponding to the maximum peak of the probability distribution

"median"

age corresponding to the median quantile of the probability distribution

"mean"

mean age weighted by probability density

"local_mode"

age corresponding to the maximum peak of the probability distribution within the confidence range specified by interval (not yet implemented)

"central"

age corresponding to the central point of the probability density within the confidence range specified by interval (not yet implemented)

interval

Numeric. Only used for method = "local_mode" and method = "central".

Value

Numeric vector the same length as x giving the point estimate for each calibrated date.

Details

If x has more than one modal value, cal_point(x, method = "mode") will return the first.

References

Michczyński A (2007). “Is it Possible to Find a Good Point Estimate of a Calibrated Radiocarbon Date?” Radiocarbon, 49(2), 393--401. ISSN 0033-8222, 1945-5755, doi:10.1017/S0033822200042326 .

Examples

cal_point(c14_calibrate(10000, 30))
#> # cal BP years <yr[1]>:
#> [1] 11400
#> # Era: Before Present (cal BP): Gregorian years (365.2425 days), counted backwards from 1950