Special method for model performance evaluation. Counts number of tp, tn, fp, fn for each subgroup (and therefore potentially distinct cutoff), sums afterwards.

group_model_performance(x, protected, cutoff, performance_metric)

## Arguments

x object created with explain factor, vector with levels as subgroups vector of thresholds for each subgroup name of performance metric

## Value

score in performance metric between 0 and 1