diff --git a/app/PersonTarget.php b/app/PersonTarget.php
index 940047e..cc0722b 100644
--- a/app/PersonTarget.php
+++ b/app/PersonTarget.php
@@ -9,7 +9,7 @@ class PersonTarget extends Model
 {
 
     /**************************************************************************
-     * PAYMENT STATES                                                         *
+     * COLLECTIONS FILTERED BY PAYMENT STATES                                 *
      **************************************************************************/
 
     /*
@@ -203,4 +203,13 @@ class PersonTarget extends Model
     public function difference() {
         return $this->signedAmount() - $this->actualsSum();
     }
+
+    /*
+     * Return true, if the target is paid and therefore closed.
+     *
+     * @return boolean
+     */
+    public function isPaid() {
+        return $this->difference() == 0;
+    }
 }