protected function convert_legacy_criterion_elements() {

        $this->write_xml('workshopform_rubric_config', array('layout' => 'list'));

        $firstelement = reset($this->elements);
        if ($firstelement === false) {
            // no elements defined in moodle.xml
            return;
        }

        // write the xml describing the artificial single rubric item
        $this->xmlwriter->begin_tag('workshopform_rubric_dimension', array('id' => $firstelement['id']));
        $this->xmlwriter->full_tag('sort', 1);
        $this->xmlwriter->full_tag('description', trim(get_string('dimensionnumber', 'workshopform_rubric', '')));
        $this->xmlwriter->full_tag('descriptionformat', FORMAT_HTML);

        foreach ($this->elements as $element) {
            $this->write_xml('workshopform_rubric_level', array(
                'id'               => $element['id'],
                'grade'            => $element['maxscore'],
                'definition'       => $element['description'],
                'definitionformat' => FORMAT_HTML
            ), array('/workshopform_rubric_level/id'));
        }

        $this->xmlwriter->end_tag('workshopform_rubric_dimension');
    }