diff --git a/admin/assignsample.php b/admin/assignsample.php
index 4ddf655a..ecd30a00 100644
--- a/admin/assignsample.php
+++ b/admin/assignsample.php
@@ -147,6 +147,12 @@ if (isset($_GET['questionnaire_id']) && isset($_GET['sample'])  && isset($_GET['
 			WHERE s.import_id = '$sid'";
 
 		$rs = $db->GetAll($sql);
+    
+    $onlyvalidemail = false;
+    if (isset($_GET['validemail'])) {
+      $onlyvalidemail = true;
+    }
+
 
     $count = 0;
 		foreach($rs as $r)
@@ -154,7 +160,7 @@ if (isset($_GET['questionnaire_id']) && isset($_GET['sample'])  && isset($_GET['
       $count++;
 		  set_time_limit(30);			
 	//only if a valid email
-      if (validate_email($r['email'])) {
+      if (!$onlyvalidemail || validate_email($r['email'])) {
         $case_id = add_case($r['sample_id'],$questionnaire_id,"NULL",$testing,41, true);
 	      if ($case_id === false) {
         	$error .= "<br/>Failed to add case for record #$count";    
@@ -451,10 +457,14 @@ if ($questionnaire_id != false)
 		
 		<?php $self_complete = $db->GetOne("SELECT self_complete FROM questionnaire WHERE questionnaire_id = '$questionnaire_id'");
 		if ($self_complete) {?>
-		<label for="generatecases" class="control-label col-lg-4"><?php echo T_("Generate cases for all sample records with a valid email address and set outcome to 'Self completion email invitation sent'?");?></label>
-		<div class="col-sm-1"><input type="checkbox" id = "generatecases" name="generatecases" class="col-sm-1" data-toggle="toggle" data-size="small" data-on="<?php echo T_("Yes");?>" data-off="<?php echo T_("No");?>" data-width="85"/></div>
+		<label for="generatecases" class="control-label col-lg-4"><?php echo T_("Generate cases for all sample records and set outcome to 'Self completion email invitation sent'?");?></label>
+		<div class="col-sm-1"><input onchange="if(this.checked==true) {$('#ve').show();} else {$('#ve').hide();}" type="checkbox" id = "generatecases" name="generatecases" class="col-sm-1" data-toggle="toggle" data-size="small" data-on="<?php echo T_("Yes");?>" data-off="<?php echo T_("No");?>" data-width="85"/></div>
 		<em class="control-label"> * <?php echo T_("Ideal if you intend to send an email invitation to sample members before attempting to call using queXS");?></em>
 		<div class='clearfix '></div></br>
+
+    <div id='ve' style='display:none'><label for="validemail" class="control-label col-lg-4"><?php echo T_("Only generate cases where there is a valid email attached?");?></label>
+		<div class="col-sm-1"><input type="checkbox" checked="checked" id = "validemail" name="validemail" class="col-sm-1" data-toggle="toggle" data-size="small" data-on="<?php echo T_("Yes");?>" data-off="<?php echo T_("No");?>" data-width="85"/></div>
+		<div class='clearfix '></div></br></div>
 		<?php }?>
 
 		<input type="hidden" name="questionnaire_id" value="<?php print($questionnaire_id);?>"/>