agree.sddm {agRee}

Mean Normalized Smallest Detectable Difference

Description

Obtain confidence interval and point estimate of the mean normalized smallest detectable difference (SDDm).

Usage

  agree.sddm(ratings, conf.level=0.95, method=c("vst", "delta"),
             NAaction=c("fail", "omit"))

Arguments

ratings

a matrix of observations with one subject per row and one rater per column.

conf.level

confidence level of the interval. The default is 0.95.

method

a character string specifying the method used to obtain confidence interval of the WSCV, based on what the SDDm is calculated. It must be one of "vst" and "delta" and may be abbreviated. The default is "vst".

NAaction

a character string specifying what should happen when the data contain NAs. It must be one of "fail" and "omit" and may be abbreviated. The default is "fail" that causes the function to print an error message and terminate if there are any incomplete observations. If it is "omit", then the entire row(s) containing incomplete observation(s) will be deleted.

Details

The calculation is based on the relationship with the WSCV and the details can be found in Baumgartner et al. (2015).

Value

Point estimate of the SDDm and lower and upper bounds of the confidence interval.

References

Richard Baumgartner, Dai Feng and Aniket Joshi (2015) Determination of smallest detectable difference for PET tracers using test-retest data: application in receptor occupancy studies (under review)

Examples

  data(petVT)
  agree.sddm(petVT$cerebellum)