A set of helper functions for paired
.
na.paired(missings = c("in.both", "fill", "asis"))
A character string denoting which action to take. See "Details", below.
na.paired
returns a function used to subset data.frames in paired
.
All methods subset out any NA time points or IDs.
"in.both"
(the default) subsets the data.frame to individuals who appear at both time points.
"fill"
adds explicit missings for the people missing second time points.
"asis"
does nothing to add or remove missings.