1 files changed, 5 insertions, 0 deletions
diff --git a/R/drfit.R b/R/drfit.R
index 4d93a6d..f3262bd 100644
--- a/R/drfit.R
+++ b/R/drfit.R
@@ -330,6 +330,11 @@ drplot <- function(drresults, data,
                 cat("will not be displayed\n")
                 ctype = "none"
             }
+        } else {
+            if (ctype != "none") {
+                stop("There are no controls in the dataset, and therefore ",
+                    "their scatter cannot be displayed\n")
+            }
         }
         lld <- log10(min(nonzerodata$dose))
         lhd <- log10(max(nonzerodata$dose))