diff --git a/R/factorial_designer.R b/R/factorial_designer.R
index ae9ef4ee..8cda096e 100644
--- a/R/factorial_designer.R
+++ b/R/factorial_designer.R
@@ -99,6 +99,8 @@ factorial_designer <- function(
   if(k < 2 || !is_integerish(k)) stop("`k' should be a positive integer > 1.")
   if(any(outcome_sds<0)) stop("`outcome_sds' should be nonnegative.")
   if(any(assignment_probs <= 0)) stop("`assignment_probs' should have positive values only.")
+  if(!is.null(sd) && !is.null(outcome_sds) && !identical(outcome_sds, rep(sd, 2^k)))
+    warning("Both `sd` and `outcome_sd` are specified and have different values. Taking value of `outcome_sds`.")
   
   # pre-objects -------------------------------------------------------------
   
diff --git a/R/two_by_two_designer.R b/R/two_by_two_designer.R
index 105b0522..12033f1f 100644
--- a/R/two_by_two_designer.R
+++ b/R/two_by_two_designer.R
@@ -78,6 +78,8 @@ two_by_two_designer <- function(N = 100,
   if(max(c(sd_i, outcome_sds) < 0) )      stop("sd_i and outcome_sds must be nonnegative")
   if(max(c(prob_A, prob_B) < 0)) stop("prob_ arguments must be nonnegative")
   if(max(c(prob_A, prob_B) > 1))  stop("prob_ arguments must not exceed 1")
+  if(!is.null(outcome_means) && all(!is.null(c(mean_A0B0, mean_A0B1, mean_A1B0, mean_A1B1))) &&
+     !identical(outcome_means, c(mean_A0B0, mean_A0B1, mean_A1B0, mean_A1B1)))  stop("Both `outcome_means` and `mean_*` parameters are specified and have different values. Taking value of `mean_*` arguments.")
   {{{
     
     # M: Model
diff --git a/tests/testthat/test_designers.R b/tests/testthat/test_designers.R
index c5d486cd..b56b1e15 100644
--- a/tests/testthat/test_designers.R
+++ b/tests/testthat/test_designers.R
@@ -249,7 +249,7 @@ test_that(desc = "two_arm_covariate_designer errors when it should",
             expect_error(two_arm_covariate_designer(rho_WZ = 10))
           })
 
-test_that(desc = "factorial_designer errors when it should",
+test_that(desc = "factorial_designer errors or warns when it should",
           code = {
             expect_error(factorial_designer(outcome_name = c("Y ")))
             expect_error(factorial_designer(outcome_means = 1, k = 2))
@@ -260,6 +260,7 @@ test_that(desc = "factorial_designer errors when it should",
             expect_error(factorial_designer(k = .5))
             expect_error(factorial_designer(outcome_sds = c(-1,-1,-1,-1), k = 2))
             expect_error(factorial_designer(assignment_probs = c(-.5,.5), k = 2))
+            expect_warning(factorial_designer(k = 2, sd = 1, outcome_sds = rep(.5, 4)))
           })
 
 test_that(desc = "process_tracing_designer errors when it should",