1. An apparatus, comprising: at least one processor; and memory storing computer-readable instructions that, when executed by the at least one processor, cause the apparatus to: forecast one or more input values corresponding to one or more input variables; calculate one or more results of a modeling function using the one or more forecasted input values; receive actual performance data corresponding to the modeling function; calculate one or more holdout values for the modeling function using the actual performance data; and plot a graph that includes the one or more results of the modeling function, the actual performance data, and the one or more holdout values for the modeling function.