diff --git a/R/pcm.R b/R/pcm.R
index f96427b..3352fa3 100644
--- a/R/pcm.R
+++ b/R/pcm.R
@@ -66,7 +66,11 @@ pcm <- function(df=NULL,items=NULL,grp=NULL,dif.items=NULL,type.dif=NULL,weights
     }
       grp <- NULL
       # prepare data
-      df <- df[,c('id',items)]
+      if (is.null(weights)) {
+        df <- df[,c('id',items)]
+      } else {
+        df <- df[,c('id',items,"weights")]
+      }
       print(df)
       colnames(df)[2:(length(colnames(df)))] <- paste0("item",seq(1,length(colnames(df))-1))
       df.long <- reshape(df,v.names=c("item"),direction="long",varying=c(items))
@@ -108,7 +112,11 @@ pcm <- function(df=NULL,items=NULL,grp=NULL,dif.items=NULL,type.dif=NULL,weights
         cat("#################################################################################################\n")
       }
       # prepare data
-      df <- df[,c('id',items,"grp")]
+      if (is.null(weights)) {
+        df <- df[,c('id',items,"grp")]
+      } else {
+        df <- df[,c('id',items,"grp","weights")]
+      }
       colnames(df)[2:(length(colnames(df))-1)] <- paste0("item",seq(1,length(colnames(df))-2))
       df.long <- reshape(df,v.names=c("item"),direction="long",varying=c(items))
       if (is.null(weights)) {
@@ -197,7 +205,11 @@ pcm <- function(df=NULL,items=NULL,grp=NULL,dif.items=NULL,type.dif=NULL,weights
         cat("#################################################################################################\n")
       }
         # prepare data
-        df <- df[,c('id',items,"grp")]
+        if (is.null(weights)) {
+          df <- df[,c('id',items,"grp")]
+        } else {
+          df <- df[,c('id',items,"grp","weights")]
+        }
         colnames(df)[2:(length(colnames(df))-1)] <- paste0("item",seq(1,length(colnames(df))-2))
         df.long <- reshape(df,v.names=c("item"),direction="long",varying=c(items))
         if (is.null(weights)) {