Censored data

The vpc_cens() function can be used to create a VPC for the probability of left- or right-censoring such as in the case of data being lower than the lower limit of quantification (ULOQ).

There is no need to add a variable to the dataset to flag the censored cases, the function only requires the lloq or uloq. Make sure you set the lloq or bloq cases to any value below or above the limit, respectively.

Note: do not set the values exactly at the limit, since then these values will be assumed to be actually measured at the limit.

The example below artificially induces an LLOQ of 5 for the above model / dataset, and generates a VPC for the probability of left-censoring.

vpc_cens(sim = simple_data$sim, obs = simple_data$obs, lloq = 30)

The vpc for the uncensored (contionuous) data will show the censoring limit as a horizontal line, and will also visualize the uncensored simulated data below lloq or above uloq:

vpc(sim = simple_data$sim, obs = simple_data$obs, lloq = 30)