quantVPC function

The quantified visual predictive check plot (QVPC)

The quantified visual predictive check visually represents actual and unavailable observations around predicted medians, regardless of the density or shape of the observed data distribution, through the form of a percent.

quantVPC(orig_data,
         sim_data,
         N_xbin = NULL,
         prob = 0.5,
         X_name = "TIME",
         Y_name = "DV",
         MissingDV = NULL,
         Kmethod = "cluster",                
         maxK = NULL,
         beta = 0.2,
         lambda = 0.3,
         R = 4,
         C1 = 2.5,
         C2 = 7.8, ...)

Arguments

• orig_data: A data frame of original data with X and Y variable.
• sim_data: A matrix of simulated data with only Y values collected.
• N_xbin: Number of bins in X variable. If NULL, optimal number of bins are automatically calcuated using optK function.
• prob: Scalar of probability.
• X_name: Name of X variable in orig_data (usually "TIME" in pharmacokinetic data).
• Y_name: Name of Y variable in orig_data (usually "DV" in pharmacokinetic data).
• MissingDV: Name of missing indicator variable in orig_data, which have value 1 if missing, value 0 otherwise. (usually "MDV" in pharmacokinetic data).
• Kmethod: The way to calculate the penalty in automatic binning."cluster" or "kernel".
• maxK: The maximum number of bins.
• beta: Additional parameter for automatic binning, used in optK function.
• lambda: Additional parameter for automatic binning, used in optK function.
• R: Additional parameter for automatic binning, used in optK function.
• C1: Additional parameter for automatic binning, used in optK function.
• C2: Additional parameter for automatic binning, used in optK function.
• ...: Arguments to be passed to methods.

Returns

quantVPC plot

Examples

data(origdata)
data(simdata)
quantVPC(origdata,simdata,prob=0.5,N_xbin=8)

References

Post, T.M., et al. (2008) Extensions to the visual predictive check for facilitate model performance evaluation, Journal of pharmacokinetics and pharmacodynamics, 35(2), 185-202