diff --git a/R/tm_outliers.R b/R/tm_outliers.R
index 12e212e2e..a7760eeec 100644
--- a/R/tm_outliers.R
+++ b/R/tm_outliers.R
@@ -42,17 +42,21 @@
 #'           )
 #'         )
 #'       ),
-#'       categorical_var = data_extract_spec(
-#'         dataname = "ADSL",
-#'         filter = filter_spec(
-#'           vars = vars,
-#'           choices = value_choices(ADSL, vars$selected),
-#'           selected = value_choices(ADSL, vars$selected),
-#'           multiple = TRUE
+#'       categorical_var = list(
+#'         data_extract_spec(
+#'           dataname = "ADSL",
+#'           filter = filter_spec(
+#'             vars = vars,
+#'             choices = value_choices(ADSL, vars$selected),
+#'             selected = value_choices(ADSL, vars$selected),
+#'             multiple = TRUE
+#'           )
 #'         )
 #'       ),
-#'       ggplot2_args = teal.widgets::ggplot2_args(
-#'         labs = list(subtitle = "Plot generated by Outliers Module")
+#'       ggplot2_args = list(
+#'         teal.widgets::ggplot2_args(
+#'           labs = list(subtitle = "Plot generated by Outliers Module")
+#'         )
 #'       )
 #'     )
 #'   )
@@ -125,13 +129,16 @@ ui_outliers <- function(id, ...) {
         id = ns("tabs"),
         tabPanel(
           "Boxplot",
-          teal.widgets::plot_with_settings_ui(id = ns("box_plot"))),
+          teal.widgets::plot_with_settings_ui(id = ns("box_plot"))
+        ),
         tabPanel(
           "Density Plot",
-          teal.widgets::plot_with_settings_ui(id = ns("density_plot"))),
+          teal.widgets::plot_with_settings_ui(id = ns("density_plot"))
+        ),
         tabPanel(
           "Cumulative Distribution Plot",
-          teal.widgets::plot_with_settings_ui(id = ns("cum_density_plot")))
+          teal.widgets::plot_with_settings_ui(id = ns("cum_density_plot"))
+        )
       ),
       br(), hr(),
       uiOutput(ns("table_ui_wrap"))
@@ -248,10 +255,11 @@ srv_outliers <- function(id, data, reporter, filter_panel_api, outlier_var,
 
     rule_diff <- function(other) {
       function(value) {
-        othervalue <- selector_list()[[other]]()[["select"]]
+        othervalue <- tryCatch(selector_list()[["categorical_var"]]()[["select"]], error = function(e) NULL)
         if (!is.null(othervalue)) {
-          if (identical(othervalue, value))
+          if (identical(othervalue, value)) {
             "`Variable` and `Categorical factor` cannot be the same"
+          }
         }
       }
     }
@@ -409,7 +417,7 @@ srv_outliers <- function(id, data, reporter, filter_panel_api, outlier_var,
                   q1_q3 <- stats::quantile(outlier_var_name, probs = c(0.25, 0.75))
                   iqr <- q1_q3[2] - q1_q3[1]
                   !(outlier_var_name >= q1_q3[1] - outlier_definition_param * iqr &
-                      outlier_var_name <= q1_q3[2] + outlier_definition_param * iqr)
+                    outlier_var_name <= q1_q3[2] + outlier_definition_param * iqr)
                 }),
                 env = list(
                   outlier_var_name = as.name(outlier_var),
@@ -558,16 +566,16 @@ srv_outliers <- function(id, data, reporter, filter_panel_api, outlier_var,
       expr = {
         if (iv_r()$is_valid()) {
           categorical_var <- as.vector(merged$anl_input_r()$columns_source$categorical_var)
-          DT::datatable(
-            common_code_q()[["summary_table"]],
-            options = list(
-              dom = "t",
-              autoWidth = TRUE,
-              columnDefs = list(list(width = "200px", targets = "_all"))
+          if (!is.null(categorical_var)) {
+            DT::datatable(
+              common_code_q()[["summary_table"]],
+              options = list(
+                dom = "t",
+                autoWidth = TRUE,
+                columnDefs = list(list(width = "200px", targets = "_all"))
+              )
             )
-          )
-        } else {
-          NULL
+          }
         }
       }
     )
diff --git a/man/tm_outliers.Rd b/man/tm_outliers.Rd
index 356f23961..e2b0931bf 100644
--- a/man/tm_outliers.Rd
+++ b/man/tm_outliers.Rd
@@ -80,17 +80,21 @@ app <- init(
           )
         )
       ),
-      categorical_var = data_extract_spec(
-        dataname = "ADSL",
-        filter = filter_spec(
-          vars = vars,
-          choices = value_choices(ADSL, vars$selected),
-          selected = value_choices(ADSL, vars$selected),
-          multiple = TRUE
+      categorical_var = list(
+        data_extract_spec(
+          dataname = "ADSL",
+          filter = filter_spec(
+            vars = vars,
+            choices = value_choices(ADSL, vars$selected),
+            selected = value_choices(ADSL, vars$selected),
+            multiple = TRUE
+          )
         )
       ),
-      ggplot2_args = teal.widgets::ggplot2_args(
-        labs = list(subtitle = "Plot generated by Outliers Module")
+      ggplot2_args = list(
+        teal.widgets::ggplot2_args(
+          labs = list(subtitle = "Plot generated by Outliers Module")
+        )
       )
     )
   )