diff --git a/grade/grading/form/rubric/lang/en/gradingform_rubric.php b/grade/grading/form/rubric/lang/en/gradingform_rubric.php
index cf9455d4bab..dacd5ddaf58 100644
--- a/grade/grading/form/rubric/lang/en/gradingform_rubric.php
+++ b/grade/grading/form/rubric/lang/en/gradingform_rubric.php
@@ -44,6 +44,7 @@ $string['err_mintwolevels'] = 'Each criterion must have at least two levels';
 $string['err_nocriteria'] = 'Rubric must contain at least one criterion';
 $string['err_nodefinition'] = 'Level definition can not be empty';
 $string['err_nodescription'] = 'Criterion description can not be empty';
+$string['err_novariations'] = 'Criterion levels cannot all be worth the same number of points';
 $string['err_scoreformat'] = 'Number of points for each level must be a valid non-negative number';
 $string['err_totalscore'] = 'Maximum number of points possible when graded by the rubric must be more than zero';
 $string['gradingof'] = '{$a} grading';
@@ -82,4 +83,6 @@ $string['showscorestudent'] = 'Display points for each level to those being grad
 $string['showscoreteacher'] = 'Display points for each level during evaluation';
 $string['sortlevelsasc'] = 'Sort order for levels:';
 $string['sortlevelsasc0'] = 'Descending by number of points';
-$string['sortlevelsasc1'] = 'Ascending by number of points';
\ No newline at end of file
+$string['sortlevelsasc1'] = 'Ascending by number of points';
+$string['zerolevelsabsent'] = 'Warning: The minimum possible score for this rubric is not 0; this can result in unexpected grades for the activity. To avoid this, each criterion should have a level with 0 points.<br>
+This warning may be ignored if a scale is used for grading, and the minimum levels in the rubric correspond to the minimum value of the scale.';
diff --git a/grade/grading/form/rubric/renderer.php b/grade/grading/form/rubric/renderer.php
index 72b6b6052d6..dbaa6661f14 100644
--- a/grade/grading/form/rubric/renderer.php
+++ b/grade/grading/form/rubric/renderer.php
@@ -633,6 +633,9 @@ class gradingform_rubric_renderer extends plugin_renderer_base {
         if (!$scores) {
             return $html;
         }
+        if ($scores['minscore'] <> 0) {
+            $html .= $this->output->notification(get_string('zerolevelsabsent', 'gradingform_rubric'), 'error');
+        }
         $html .= $this->box(
                 html_writer::tag('h4', get_string('rubricmapping', 'gradingform_rubric')).
                 html_writer::tag('div', get_string('rubricmappingexplained', 'gradingform_rubric', (object)$scores))
diff --git a/grade/grading/form/rubric/rubriceditor.php b/grade/grading/form/rubric/rubriceditor.php
index 54601b51090..49b0193446f 100644
--- a/grade/grading/form/rubric/rubriceditor.php
+++ b/grade/grading/form/rubric/rubriceditor.php
@@ -197,6 +197,7 @@ class MoodleQuickForm_rubriceditor extends HTML_QuickForm_input {
         // iterate through criteria
         $lastaction = null;
         $lastid = null;
+        $overallminscore = $overallmaxscore = 0;
         foreach ($value['criteria'] as $id => $criterion) {
             if ($id == 'addcriterion') {
                 $id = $this->get_next_id(array_keys($value['criteria']));
@@ -221,7 +222,7 @@ class MoodleQuickForm_rubriceditor extends HTML_QuickForm_input {
                 $this->nonjsbuttonpressed = true;
             }
             $levels = array();
-            $maxscore = null;
+            $minscore = $maxscore = null;
             if (array_key_exists('levels', $criterion)) {
                 foreach ($criterion['levels'] as $levelid => $level) {
                     if ($levelid == 'addlevel') {
@@ -249,6 +250,9 @@ class MoodleQuickForm_rubriceditor extends HTML_QuickForm_input {
                             }
                         }
                         $levels[$levelid] = $level;
+                        if ($minscore === null || (float)$level['score'] < $minscore) {
+                            $minscore = (float)$level['score'];
+                        }
                         if ($maxscore === null || (float)$level['score'] > $maxscore) {
                             $maxscore = (float)$level['score'];
                         }
@@ -268,6 +272,8 @@ class MoodleQuickForm_rubriceditor extends HTML_QuickForm_input {
                     $errors['err_nodescription'] = 1;
                     $criterion['error_description'] = true;
                 }
+                $overallmaxscore += $maxscore;
+                $overallminscore += $minscore;
             }
             if (array_key_exists('moveup', $criterion) || $lastaction == 'movedown') {
                 unset($criterion['moveup']);
@@ -307,6 +313,9 @@ class MoodleQuickForm_rubriceditor extends HTML_QuickForm_input {
 
         // create validation error string (if needed)
         if ($withvalidation) {
+            if ($overallminscore == $overallmaxscore) {
+                $errors['err_novariations'] = 1;
+            }
             if (count($errors)) {
                 $rv = array();
                 foreach ($errors as $error => $v) {