diff --git a/voting_rules.rules.inc b/voting_rules.rules.inc
index 8a9a644..76f618c 100644
--- a/voting_rules.rules.inc
+++ b/voting_rules.rules.inc
@@ -38,6 +38,11 @@ function voting_rules_rules_data_info() {
       'description' => t('The value of the vote.'),
       'type' => 'decimal',
     ),
+    'previous_value' => array(
+      'label' => t('Previous Value'),
+      'description' => t('The previous value of the vote.'),
+      'type' => 'decimal',
+    ),
     'timestamp' => array(
       'label' => t('Date'),
       'description' => t('The date of the vote.'),