diff --git a/NAMESPACE b/NAMESPACE
index 6d0067d..10d7ddd 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -67,6 +67,7 @@ export(plotPCA)
 export(plotSNVInfo)
 export(plotSNVSummary)
 export(plotStackedBarPlot)
+export(rankComponents)
 export(returnGenes)
 export(reverseAnnot)
 export(setAnnotation)
diff --git a/R/doGSEA.R b/R/doGSEA.R
index 8262700..2a5909c 100644
--- a/R/doGSEA.R
+++ b/R/doGSEA.R
@@ -214,6 +214,7 @@ addGeneAbundance <- function(stana, candSp, IDs,
 #' @param l2 level2
 #' @param method gmean, amean, or t
 #' @param eps pseudocount added when calculating log
+#' @return named vector of statistical values
 #' @noRd
 L2FC <- function(mat, l1, l2, method="t", eps=0) {
     if (method == "gmean") {
diff --git a/R/rankComponents.R b/R/rankComponents.R
new file mode 100644
index 0000000..df642e2
--- /dev/null
+++ b/R/rankComponents.R
@@ -0,0 +1,51 @@
+#' rankComponents
+#' 
+#' Returns the rank of the components in the graph
+#' based on the statistical values inside the graph.
+#' 
+#' @param stana stana object
+#' @param candSp candidate species
+#' @param pid KEGG pathway ID
+#' @param cl if NULL, grouping in stana is used
+#' @param eps pseudovalue added if log is taken
+#' @param how how to combine multiple variables, default to sum
+#' @param rankMethod how to rank genes
+#' @param statHow how to aggregate the multiple statistical values
+#' @export
+rankComponents <- function(stana, pid, candSp=NULL, cl=NULL, eps=1e-2, how=sum,
+    zeroPerc=0, rankMethod="modt", statHow=mean) {
+    if (is.null(candSp)) {candSp <- stana@ids[1]}
+    if (is.null(cl)) {cl <- stana@cl}
+    if (length(cl)!=2) {stop("Only the two group is supported")}
+
+    if (is.null(stana@kos[[candSp]])) {
+        ko_tbl <- summariseAbundance(stana,sp = candSp,
+                    checkEGGNOG(annot_file=stana@eggNOG[[candSp]], "KEGG_ko"),
+                    how=how)
+        stana@kos[[candSp]] <- ko_tbl
+    } else {
+        ko_tbl <- stana@kos[[candSp]]
+        cat_subtle("# Using pre-computed KO table\n")
+    }
+
+    ## eps values
+    cat_subtle("# ", names(cl)[1], " / ", names(cl)[2], "\n", sep="")
+    ko_sum <- L2FC(ko_tbl, cl[[1]], cl[[2]], method=rankMethod, eps=eps)
+    ## KO to PATHWAY mapping
+    gg <- ggkegg::pathway(pid)
+    gg <- gg %>% mutate(stat=ggkegg::node_numeric(ko_sum))
+
+    types <- gg %N>% pull(type)
+    ind <- which(types=="compound")
+
+
+    rankVals <- lapply(ind, function(i) {
+        candidate_reac <- gg %E>% dplyr::filter(to == i | from == i) %>% dplyr::pull(reaction)
+        vals <- gg %N>% dplyr::filter(reaction %in% candidate_reac) %>% dplyr::pull(stat)
+        do.call(statHow, list(x=vals))
+    }) %>% unlist()
+
+    gg %N>% dplyr::filter(type=="compound") %>% data.frame() %>%
+        mutate(rank=rankVals) %>% arrange(desc(rank)) %>%
+        select(name, rank) %>% na.omit()
+}
diff --git a/man/rankComponents.Rd b/man/rankComponents.Rd
new file mode 100644
index 0000000..089fb53
--- /dev/null
+++ b/man/rankComponents.Rd
@@ -0,0 +1,39 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/rankComponents.R
+\name{rankComponents}
+\alias{rankComponents}
+\title{rankComponents}
+\usage{
+rankComponents(
+  stana,
+  pid,
+  candSp = NULL,
+  cl = NULL,
+  eps = 0.01,
+  how = sum,
+  zeroPerc = 0,
+  rankMethod = "modt",
+  statHow = mean
+)
+}
+\arguments{
+\item{stana}{stana object}
+
+\item{pid}{KEGG pathway ID}
+
+\item{candSp}{candidate species}
+
+\item{cl}{if NULL, grouping in stana is used}
+
+\item{eps}{pseudovalue added if log is taken}
+
+\item{how}{how to combine multiple variables, default to sum}
+
+\item{rankMethod}{how to rank genes}
+
+\item{statHow}{how to aggregate the multiple statistical values}
+}
+\description{
+Returns the rank of the components in the graph
+based on the statistical values inside the graph.
+}