diff --git a/R/Bootstrap.R b/R/Bootstrap.R
index 64a1969..df66d74 100644
--- a/R/Bootstrap.R
+++ b/R/Bootstrap.R
@@ -1,210 +1,219 @@
 # Copyright (c) German Cancer Research Center (DKFZ)
 # All rights reserved.
 #
 # This file is part of challengeR.
 #
 # challengeR is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
 # the Free Software Foundation, either version 2 of the License, or
 # (at your option) any later version.
 #
 # challengeR is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License
 # along with challengeR. If not, see <https://www.gnu.org/licenses/>.
 
 bootstrap <- function(object,...) UseMethod("bootstrap")
 bootstrap.default <- function(object, ...) stop("not implemented for this class")
 
 
 #' Performs bootstrapping
 #'
 #' Performs bootstrapping on a ranked assessment data set and applies the ranking method to each bootstrap sample. One bootstrap sample of
 #' a task with \code{n} cases consists of \code{n} cases randomly drawn with replacement from this task.
 #' A total of \code{nboot} of these bootstrap samples are drawn.
 #'
 #' @param object The ranked assessment data set.
 #' @param nboot The number of bootstrap samples.
 #' @param parallel A boolean specifying whether parallel processing should be enabled.
 #' @param progress A string specifying the type of progress indication.
 #' @param ... Further arguments passed to or from other functions.
 #'
 #' @return An S3 object of class "bootstrap.list" to represent a bootstrapped, ranked assessment data set.
 #'
 #' @examples
 #'
 #' \dontrun{
 #'  # perform bootstrapping with 1000 bootstrap samples using one CPU
 #'  set.seed(1)
 #'  ranking_bootstrapped <- bootstrap(ranking, nboot = 1000)
 #' }
 #'
 #' \dontrun{
 #'  # perform bootstrapping using multiple CPUs (here: 8 CPUs)
 #'  library(doParallel)
 #'  registerDoParallel(cores=8)
 #'  set.seed(1)
 #'  ranking_bootstrapped <- bootstrap(ranking, nboot = 1000, parallel = TRUE, progress = "none")
 #'  stopImplicitCluster()
 #' }
 #'
 #' @export
 bootstrap.ranked.list=function(object,
                                nboot,
                                parallel=FALSE,
                                progress="text",
                                ...){
   algorithm=attr(object$data,"algorithm")
   by=attr(object$data,"case")
 
   # exclude if only 1 test case or only 1 algorithm
   tidy.data.id=sapply(object$data,
                       function(data.subset) {
                         ifelse((length(unique(data.subset[[by]]))==1 |  length(unique(data.subset[[algorithm]]))<=1 ),
                                yes=FALSE,
                                no=TRUE)
                         })
+  
+  if (sum(tidy.data.id)==0) {
+    if (length(object$matlist)>1) stop("All tasks only contained 1 test case. Bootstrapping with 1 test case not sensible.")
+    else stop("Only 1 test case included. Bootstrapping with 1 test case not sensible.")
+  }
+  if (sum(tidy.data.id)<length(object$matlist)) message("Task(s) ", 
+                                                        paste(names(tidy.data.id)[!tidy.data.id], collapse = ", "),
+                                                        " with only 1 test case excluded from bootstrapping.")   
+  
   tidy.data=object$data[tidy.data.id]
   tidy.matlist=object$matlist[tidy.data.id]
 
   res= llply(1:nboot,
              function(it){
                # draw 1 sample for each task
                bootDatalist = lapply(tidy.data, function(data.subset) {
                  index = unique(data.subset[[by]])
 
                  # bootIndex=sample(index,size=length(index),replace=TRUE)
                  # bootData=bind_rows(lapply(bootIndex,function(zz) data.subset[data.subset[[by]]==zz,]))
                  # faster:
                  bootIndex = data.frame(sample(index,
                                                size = length(index),
                                                replace = TRUE))
                  colnames(bootIndex) = by
                  bootData = merge(bootIndex,
                                   data.subset,
                                   by = by)
                  bootData
                })
                attr(bootDatalist, "inverseOrder") = attr(object$data, "inverseOrder")
                attr(bootDatalist, "algorithm") = attr(object$data, "algorithm")
                attr(bootDatalist, "case") = attr(object$data, "case")
                attr(bootDatalist, "check") = FALSE
                object$FUN(bootDatalist)$mat
              },
              .parallel = parallel,
              .progress = progress)
 
   rankmatlist = lapply(res[[1]],
                        function(z) z[, "rank", drop = F]
                        )
   for (j in 2:length(res)) {
     rankmatlist = quickmerge.list(rankmatlist,
                                   lapply(res[[j]],
                                          function(z)  z[, "rank", drop = F]))
   }
 
   aggmatlist = lapply(res[[1]],
                       function(z) z[, -2, drop = F])
   for (j in 2:length(res)) {
     aggmatlist = quickmerge.list(aggmatlist,
                                  lapply(res[[j]],
                                         function(z) z[, -2, drop = F]))
   }
 
   final=list(bootsrappedRanks=rankmatlist,
              bootsrappedAggregate=aggmatlist,
              data=object$data,
              matlist=tidy.matlist,
              FUN=object$FUN,
              FUN.list=object$FUN.list)
   class(final)=c("bootstrap.list")
   final
 }
 
 
 
 
 
 
 ####################################################################################################
 # deprecate following functions?
 
 
 
 rankFrequencies <- function(object,...) UseMethod("rankFrequencies")
 rankFrequencies.default <- function(object, ...) stop("not implemented for this class")
 
 rankFrequencies.bootstrap=function(object, who,...){
   if (is.data.frame(who)) who=rownames(who)
   if (length(who)==1){
     res=table(t(object$bootsrappedRanks[rownames(object$bootsrappedRanks)==who,]))
     cat("\n",who,"\n")
     print(res)
   } else {
     res=lapply(who, function(w){
       rr=table(t(object$bootsrappedRanks[rownames(object$bootsrappedRanks)==w,]))
     cat(w,"\n")
       print(rr)
       cat("\n")
       rr
     })
   }
   res=c(list(rankFrequencies=res),object)
   invisible(res)
 }
 
 rankFrequencies.bootstrap.list=function(object, who,...){
   if (is.data.frame(who)) who=rownames(who)
   res=lapply(object$bootsrappedRanks,function(bootMat){
     if (length(who)==1){
       res=table(t(bootMat[rownames(bootMat)==who,]))
       cat("\n",who,"\n")
       print(res)
     } else {
       res=lapply(who, function(w){
         rr=table(t(bootMat[rownames(bootMat)==w,]))
         cat(w,"\n")
         print(rr)
         cat("\n")
         rr
       })
     }
     res
   })
   res=c(list(rankFrequencies=res),object)
   invisible(res)
 }
 
 
 
 
 winnerFrequencies <- function(object,...) UseMethod("winnerFrequencies")
 winnerFrequencies.default <- function(object, ...) stop("not implemented for this class")
 
 # Achtung: bester rank muss ==1 sein und nicht z.B. 1.5
 winnerFrequencies.bootstrap=function(object,...){
   rankings_dicho=ifelse(object$bootsrappedRanks==1,1,0)
   winnerFrequencies=data.frame(winnerFrequency=rowSums(rankings_dicho),row.names = rownames(object$bootsrappedRanks))
   res=merge(object$mat,winnerFrequencies,by="row.names",...)
   rownames(res)=res[,1]
   res=res[,-1]
   # res=c(res=res,object)
   # class(res)="bootstrapResults"
   res
 }
 
 winnerFrequencies.bootstrap.list=function(object,...){
   res=lapply(1:length(object$bootsrappedRanks),function(id){
     rankings_dicho=ifelse(object$bootsrappedRanks[[id]]==1,1,0)
     winnerFrequencies=data.frame(winnerFrequency=rowSums(rankings_dicho),row.names = rownames(object$bootsrappedRanks[[id]]))
     res=merge(object$matlist[[id]],winnerFrequencies,by="row.names",...)
     rownames(res)=res[,1]
     res=res[,-1]
     res
   })
   names(res)=names(object$bootsrappedRanks)
   res
 }