diff --git a/R/check_input.R b/R/check_input.R
index 75d4165..3e68ebf 100644
--- a/R/check_input.R
+++ b/R/check_input.R
@@ -8,6 +8,7 @@ check_input <- function(argument_name, input_value) {
   if(argument_name %in% geq0) check_geq(argument_name, input_value, min = 0)
   else if(argument_name %in% geq1) check_geq(argument_name, input_value, min = 1)
   else if(argument_name %in% range) check_in_range(argument_name, input_value)
+  else if(argument_name == "correlation") check_rho(input_value)
   else if(argument_name == "form") check_form(input_value)
   else if(argument_name == "real_scale") check_scale(input_value)
   else if(argument_name == "cost_cluster") check_cost_cluster(input_value)
diff --git a/tests/testthat/test-fisher_information.R b/tests/testthat/test-fisher_information.R
index 564027d..b1fade6 100644
--- a/tests/testthat/test-fisher_information.R
+++ b/tests/testthat/test-fisher_information.R
@@ -150,7 +150,7 @@ test_that("fi_pool_cluster() fails when integral input parameters are so extreme
 })
 
 test_that("fi_pool_cluster() fails when likelihoods or derivatives do not add up", {
-  # SLOW (doesn't scale with pool size, number, and vector length)
+  # Previously did not scale with pool size, number, and vector length
   expect_error(
     fi_pool_cluster(
       pool_size = c(5, 10),