Check for non-systematic discounting, per the Johnson & Bickel (2008) criteria. These are:
C1: No indifference point can exceed the previous by more than 0.2
C2: Last indifference point must be lower than first by at least 0.1
Value
Named logical vector specifying whether nonsystematic discounting is exhibited according to C1/C2.
Examples
if (FALSE) { # \dontrun{
# On a model
data("td_bc_single_ptpt")
mod <- td_bcnm(td_bc_single_ptpt, discount_function = 'model-free')
any(nonsys(mod))
# On a dataframe
data("td_ip_simulated_ptpt")
any(nonsys(td_ip_simulated_ptpt))
# Artificial case of nonsystematic discounting
nonsys(data.frame(del = 1:3, indiff = c(0.5, 0.8, 0.6))) # Both TRUE
} # }