diff --git a/mod/quiz/report/statistics/db/install.xml b/mod/quiz/report/statistics/db/install.xml
index bc9313a6269..1410e39837b 100644
--- a/mod/quiz/report/statistics/db/install.xml
+++ b/mod/quiz/report/statistics/db/install.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8" ?>
-<XMLDB PATH="mod/quiz/report/statistics/db" VERSION="20080724" COMMENT="XMLDB file for Moodle mod/quiz/report/statistics"
+<XMLDB PATH="mod/quiz/report/statistics/db" VERSION="20080725" COMMENT="XMLDB file for Moodle mod/quiz/report/statistics"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:noNamespaceSchemaLocation="../../../../../lib/xmldb/xmldb.xsd"
 >
@@ -32,8 +32,9 @@
         <FIELD NAME="id" TYPE="int" LENGTH="10" NOTNULL="true" UNSIGNED="true" SEQUENCE="true" ENUM="false" NEXT="quizstatisticsid"/>
         <FIELD NAME="quizstatisticsid" TYPE="int" LENGTH="10" NOTNULL="true" UNSIGNED="true" SEQUENCE="false" ENUM="false" PREVIOUS="id" NEXT="questionid"/>
         <FIELD NAME="questionid" TYPE="int" LENGTH="10" NOTNULL="true" UNSIGNED="true" SEQUENCE="false" ENUM="false" PREVIOUS="quizstatisticsid" NEXT="subquestion"/>
-        <FIELD NAME="subquestion" TYPE="int" LENGTH="4" NOTNULL="true" UNSIGNED="true" SEQUENCE="false" ENUM="false" PREVIOUS="questionid" NEXT="effectiveweight"/>
-        <FIELD NAME="effectiveweight" TYPE="number" LENGTH="15" NOTNULL="false" UNSIGNED="true" SEQUENCE="false" ENUM="false" DECIMALS="5" PREVIOUS="subquestion" NEXT="discriminationindex"/>
+        <FIELD NAME="subquestion" TYPE="int" LENGTH="4" NOTNULL="true" UNSIGNED="true" SEQUENCE="false" ENUM="false" PREVIOUS="questionid" NEXT="s"/>
+        <FIELD NAME="s" TYPE="int" LENGTH="10" NOTNULL="true" UNSIGNED="true" DEFAULT="0" SEQUENCE="false" ENUM="false" PREVIOUS="subquestion" NEXT="effectiveweight"/>
+        <FIELD NAME="effectiveweight" TYPE="number" LENGTH="15" NOTNULL="false" UNSIGNED="true" SEQUENCE="false" ENUM="false" DECIMALS="5" PREVIOUS="s" NEXT="discriminationindex"/>
         <FIELD NAME="discriminationindex" TYPE="number" LENGTH="15" NOTNULL="false" UNSIGNED="false" SEQUENCE="false" ENUM="false" DECIMALS="5" PREVIOUS="effectiveweight" NEXT="discriminativeefficiency"/>
         <FIELD NAME="discriminativeefficiency" TYPE="number" LENGTH="15" NOTNULL="false" UNSIGNED="false" SEQUENCE="false" ENUM="false" DECIMALS="5" PREVIOUS="discriminationindex" NEXT="sd"/>
         <FIELD NAME="sd" TYPE="number" LENGTH="15" NOTNULL="false" UNSIGNED="true" SEQUENCE="false" ENUM="false" DECIMALS="10" PREVIOUS="discriminativeefficiency" NEXT="facility"/>
diff --git a/mod/quiz/report/statistics/db/upgrade.php b/mod/quiz/report/statistics/db/upgrade.php
index 23c5e2f65b6..b2893f95843 100644
--- a/mod/quiz/report/statistics/db/upgrade.php
+++ b/mod/quiz/report/statistics/db/upgrade.php
@@ -14,6 +14,18 @@ function xmldb_quizreport_statistics_upgrade($oldversion=0) {
         //register cron to run every 5 hours.
         $result = $result && $DB->set_field('quiz_report', 'cron', HOURSECS*5, array('name'=>'statistics'));
     }
+    if ($result && $oldversion < 2008072500) {
+
+    /// Define field s to be added to quiz_question_statistics
+        $table = new xmldb_table('quiz_question_statistics');
+        $field = new xmldb_field('s', XMLDB_TYPE_INTEGER, '10', XMLDB_UNSIGNED, XMLDB_NOTNULL, null, null, null, '0', 'subquestion');
+
+    /// Conditionally launch add field s
+        if (!$dbman->field_exists($table, $field)) {
+            $dbman->add_field($table, $field);
+        }
+
+    }
     return $result;
 }
 
diff --git a/mod/quiz/report/statistics/version.php b/mod/quiz/report/statistics/version.php
index f872ee95f14..b522d2d478f 100644
--- a/mod/quiz/report/statistics/version.php
+++ b/mod/quiz/report/statistics/version.php
@@ -1,4 +1,4 @@
 <?php
-$plugin->version  = 2008072401;   // The (date) version of this module
+$plugin->version  = 2008072500;   // The (date) version of this module
 
 ?>
\ No newline at end of file