as.Dates                Converting potential date to Date vector
as.incadata             Coerce to object of class "incadata"
ex_data                 Example data from INCA
id                      Add id variables to data frame
is.incalogical          Coerce to logical if value is logical according
                        to INCA
lt                      Lead time from one date to another
use_incadata            Use incadata from file or dataframe df
