diff --git a/pivot-table.el b/pivot-table.el
index d0dfe59..08ae585 100644
--- a/pivot-table.el
+++ b/pivot-table.el
@@ -27,9 +27,9 @@
   "Build a pivot table
 
 TODO: more documentation"
-  (let* ((rows (assoc :rows params))
-         (cols (assoc :cols params))
-         (vals (assoc :vals params))
+  (let* ((rows (plist-get params :rows))
+         (cols (plist-get params :cols))
+         (vals (plist-get params :vals))
          (col-index (pt-get-columns source))
          (index (pt-column-names source))
          src-cols