diff --git a/R/clustering-outl-spc.R b/R/clustering-outl-spc.R
index e69de29..556972c 100644
--- a/R/clustering-outl-spc.R
+++ b/R/clustering-outl-spc.R
@@ -0,0 +1,30 @@
+## Robust multivariate outlier detection method based on semi-robust principal
+## components ==================================================================
+
+# Apply pcout for a nested list of matrices at a certain depth
+pcout_depth <- function(x, depth = 2) {
+  purrr::modify_depth(.x = x, .depth = depth,
+    .f = ~ mvoutlier::pcout(x = ., makeplot = FALSE))
+}
+
+# Extracts mvoutlier::pcout $wscat elements in nested list (default at depth 2)
+wscat_depth <- function(x, depth = 2) {
+  purrr::modify_depth(.x = x, .depth = 2, .f = "wscat")
+}
+
+# Returns nested list containing logicals from test which scattering weights
+# are zero
+which_wscat0_depth <- function(x) {
+  purrr::modify_depth(wscat_depth(x), 2, ~ . == 0)
+}
+
+# Extract $wfinal01 elements
+wfinal01_depth <- function(x) {
+  purrr::modify_depth(x, 2, "wfinal01")
+}
+
+# Returns nested list containing logicals from test which final 0/1 weights
+# are zero
+which_wfinal0_depth <- function(x) {
+  purrr::modify_depth(wfinal01_depth(x), 2, ~ . == 0)
+}