diff --git a/instat/static/InstatObject/R/data_object_R6.R b/instat/static/InstatObject/R/data_object_R6.R
index 00ea4778cc..a92de3fcbd 100644
--- a/instat/static/InstatObject/R/data_object_R6.R
+++ b/instat/static/InstatObject/R/data_object_R6.R
@@ -693,9 +693,9 @@ DataSheet$set("public", "add_columns_to_data", function(col_name = "", col_data,
     }
   }
   
-  if(length(col_name) != num_cols) {
+  if(length(col_name) != num_cols && (num_cols == 1 || length(col_name) == 1)) {
     use_col_name_as_prefix = TRUE
-  }
+  } else use_col_name_as_prefix = FALSE
   
   replaced <- FALSE
   previous_length = self$get_column_count()
@@ -712,8 +712,10 @@ DataSheet$set("public", "add_columns_to_data", function(col_name = "", col_data,
       if(require_correct_length) stop("Length of new column must be divisible by the length of the data frame")
       else curr_col <- rep(curr_col, length.out = self$get_data_frame_length())
     }
-    if(use_col_name_as_prefix) curr_col_name = self$get_next_default_column_name(col_name[i])
-    else curr_col_name = col_name[[i]]
+print(use_col_name_as_prefix)
+    if(use_col_name_as_prefix) curr_col_name = self$get_next_default_column_name(col_name)
+    else curr_col_name = col_name[i]
+
     curr_col_name <- make.names(iconv(curr_col_name, to = "ASCII//TRANSLIT", sub = "."))
     new_col_names <- c(new_col_names, curr_col_name)
     if(curr_col_name %in% self$get_column_names()) {