An aggregation method reduces the performance values of the test (and possibly the training sets) to a single value. To see all possible implemented aggregations look at aggregations.
The aggregation can access all relevant information of the result after resampling and combine them into a single value. Though usually something very simple like taking the mean of the test set performances is done.
Name of the aggregation method.
Long name of the aggregation method.
Properties of the aggregation.