diff --git a/DESCRIPTION b/DESCRIPTION
index cc97264..850eb85 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -2,7 +2,7 @@ Package: simPop
 Type: Package
 Title: Simulation of Complex Synthetic Data
     Information
-Version: 2.1.2
+Version: 2.1.3
 Date: 2022-11-06
 Authors@R: c(
   person("Matthias", "Templ", email = "matthias.templ@gmail.com", role = c("aut","cre")),
@@ -102,5 +102,5 @@ Collate:
     'whipple.R'
     'dataSets.R'
     'zzz.R'
-RoxygenNote: 7.2.2
+RoxygenNote: 7.2.3
 Encoding: UTF-8
diff --git a/R/simCategorical.R b/R/simCategorical.R
index 5fbeb36..7cac9fe 100644
--- a/R/simCategorical.R
+++ b/R/simCategorical.R
@@ -65,7 +65,9 @@ generateValues <- function(dataSample, dataPop, params) {
     }else if ( meth %in% c("ctree","cforest") ) {
       probs <- predict(mod, newdata=data.table(newdata), type="prob")
       probs <- split(probs, seq(nrow(probs)))  
-      probs <- do.call("rbind",probs)
+      if(!inherits(probs,"matrix")){
+        probs <- do.call("rbind",probs)
+      }
 	    if(ncol(probs)==2){
         probs <- probs[,2]
 	    }
diff --git a/R/specifyInput.R b/R/specifyInput.R
index 8f63bff..a1ca86b 100644
--- a/R/specifyInput.R
+++ b/R/specifyInput.R
@@ -35,6 +35,10 @@
 #' inp
 specifyInput <- function(data, hhid, hhsize=NULL, pid=NULL, weight=NULL,
                          strata=NULL, population=FALSE) {
+  
+  if(!(inherits(data,"data.frame") | inherits(data,"data.table"))){
+    stop("data must be either a data.frame or data.table")
+  }
   if ( !inherits(hhid, "character") | length(hhid) != 1 | is.na(match(hhid, colnames(data)))) {
     stop("hhid must be a character defining the variable holding household ids and must be of length 1!\n")
   }
@@ -54,6 +58,10 @@ specifyInput <- function(data, hhid, hhsize=NULL, pid=NULL, weight=NULL,
     if(!inherits(data[[strata]], "factor")){
       stop(strata," is not a factor variable as needed for a strata variable.")
     }
+  }else{
+    # initialize dummy strata used by other methods in package
+    strata <- paste(c("DUMMY_STRATA_",sample(c(letters,LETTERS),8,replace=TRUE)), collapse="")
+    df[[strata]] <- factor(1)
   }
 
   data <- as.data.table(data)