- test.mean 
 Mean of performance values on test sets.
- test.sd 
 Standard deviation of performance values on test sets.
- test.median 
 Median of performance values on test sets.
- test.min 
 Minimum of performance values on test sets.
- test.max 
 Maximum of performance values on test sets.
- test.sum 
 Sum of performance values on test sets.
- train.mean 
 Mean of performance values on training sets.
- train.sd 
 Standard deviation of performance values on training sets.
- train.median 
 Median of performance values on training sets.
- train.min 
 Minimum of performance values on training sets.
- train.max 
 Maximum of performance values on training sets.
- train.sum 
 Sum of performance values on training sets.
- b632 
 Aggregation for B632 bootstrap.
- b632plus 
 Aggregation for B632+ bootstrap.
- testgroup.mean 
 Performance values on test sets are grouped according to resampling method. The mean for every group is calculated, then the mean of those means. Mainly used for repeated CV.
- testgroup.sd 
 Similar to testgroup.mean - after the mean for every group is calculated, the standard deviation of those means is obtained. Mainly used for repeated CV.
- test.join 
 Performance measure on joined test sets. This is especially useful for small sample sizes where unbalanced group sizes have a significant impact on the aggregation, especially for cross-validation test.join might make sense now. For the repeated CV, the performance is calculated on each repetition and then aggregated with the arithmetic mean.
