diff --git a/R/RMS.R b/R/RMS.R
index c059c8f7ba36bb83d1915c171f6f3855b4c5d4b2..c2cb8bccd5405fae4bcb31aeb35119818c3cf187 100644
--- a/R/RMS.R
+++ b/R/RMS.R
@@ -11,9 +11,13 @@
 #'The confidence interval is computed by the chi2 distribution.\cr
 #'
 #'@param exp A named numeric array of experimental data, with at least two 
-#'  dimensions 'time_dim' and 'dat_dim'.
+#'  dimensions 'time_dim' and 'dat_dim'. It can also be a vector with the 
+#'  same length as 'obs', then the vector will automatically be 'time_dim' and 
+#'  'dat_dim' will be 1.
 #'@param obs A named numeric array of observational data, same dimensions as  
-#'  parameter 'exp' except along dat_dim.
+#'  parameter 'exp' except along dat_dim. It can also be a vector with the same
+#'  length as 'exp', then the vector will automatically be 'time_dim' and 
+#'  'dat_dim' will be 1.
 #'@param time_dim A character string indicating the name of dimension along  
 #'  which the correlations are computed. The default value is 'sdate'.
 #'@param dat_dim A character string indicating the name of member (nobs/nexp) 
@@ -73,9 +77,19 @@ RMS <- function(exp, obs, time_dim = 'sdate', dat_dim = 'dataset',
   if (!is.numeric(exp) | !is.numeric(obs)) {
     stop("Parameter 'exp' and 'obs' must be a numeric array.")
   }
-  if (is.null(dim(exp)) | is.null(dim(obs))) {
-    stop(paste0("Parameter 'exp' and 'obs' must be at least two dimensions ",
-                "containing time_dim and dat_dim."))
+  if (is.null(dim(exp)) & is.null(dim(obs))) {  #is vector
+    if (length(exp) == length(obs)) {
+      exp <- array(exp, dim = c(length(exp), 1))
+      names(dim(exp)) <- c(time_dim, dat_dim)
+      obs <- array(obs, dim = c(length(obs), 1))
+      names(dim(obs)) <- c(time_dim, dat_dim)
+    } else {
+    stop(paste0("Parameter 'exp' and 'obs' must be array with as least two ",
+                "dimensions time_dim and dat_dim, or vector of same length."))
+    }
+  } else if (is.null(dim(exp)) | is.null(dim(obs))) {
+    stop(paste0("Parameter 'exp' and 'obs' must be array with as least two ",
+                "dimensions time_dim and dat_dim, or vector of same length."))
   }
   if(any(is.null(names(dim(exp))))| any(nchar(names(dim(exp))) == 0) |
      any(is.null(names(dim(obs))))| any(nchar(names(dim(obs))) == 0)) {
diff --git a/man/RMS.Rd b/man/RMS.Rd
index 3ac1359ea069fd63b1765be06c91d31bebeb5f5e..7bd33b3ae69f711813806ff2dd266147791e8c7d 100644
--- a/man/RMS.Rd
+++ b/man/RMS.Rd
@@ -9,10 +9,14 @@ RMS(exp, obs, time_dim = "sdate", dat_dim = "dataset", comp_dim = NULL,
 }
 \arguments{
 \item{exp}{A named numeric array of experimental data, with at least two 
-dimensions 'time_dim' and 'dat_dim'.}
+dimensions 'time_dim' and 'dat_dim'. It can also be a vector with the 
+same length as 'obs', then the vector will automatically be 'time_dim' and 
+'dat_dim' will be 1.}
 
 \item{obs}{A named numeric array of observational data, same dimensions as
-parameter 'exp' except along dat_dim.}
+parameter 'exp' except along dat_dim. It can also be a vector with the same
+length as 'exp', then the vector will automatically be 'time_dim' and 
+'dat_dim' will be 1.}
 
 \item{time_dim}{A character string indicating the name of dimension along
 which the correlations are computed. The default value is 'sdate'.}
diff --git a/tests/testthat/test-RMS.R b/tests/testthat/test-RMS.R
index 7b3e7b973cf09cf8ad5840945a434af75ffb71c7..35ea4e9da46c735dbec28ba59f9412f60cfffb08 100644
--- a/tests/testthat/test-RMS.R
+++ b/tests/testthat/test-RMS.R
@@ -11,6 +11,13 @@ context("s2dv::RMS tests")
   na <- floor(runif(10, min = 1, max = 80))
   obs1[na] <- NA
 
+  # dat 2: vector
+  set.seed(5)
+  exp2 <- rnorm(10)
+  set.seed(6)
+  obs2 <- rnorm(10)
+
+
 ##############################################
 test_that("1. Input checks", {
 
@@ -24,8 +31,7 @@ test_that("1. Input checks", {
   )
   expect_error(
   RMS(c(1:10), c(2:4)),
-  paste0("Parameter 'exp' and 'obs' must be at least two dimensions ",
-         "containing time_dim and dat_dim.")
+  "Parameter 'exp' and 'obs' must be array with as least two dimensions time_dim and dat_dim, or vector of same length."
   )
   expect_error(
   RMS(array(1:10, dim = c(2, 5)), array(1:4, dim = c(2, 2))),
@@ -147,4 +153,18 @@ test_that("2. Output checks: dat1", {
 })
 
 ##############################################
+test_that("3. Output checks: dat2", {
+
+  expect_equal(
+    dim(RMS(exp2, obs2)$rms),
+    c(nexp = 1, nobs = 1)
+  )
 
+  expect_equal(
+  as.vector(RMS(exp2, obs2)$rms),
+  1.429815,
+  tolerance = 0.00001
+  )
+})
+
+##############################################