protected function definition_sub() {
        $mform = $this->_form;

        $plugindefaults = get_config('workshopeval_best');
        $current = $this->_customdata['current'];

        $options = array();
        for ($i = 9; $i >= 1; $i = $i-2) {
            $options[$i] = get_string('comparisonlevel' . $i, 'workshopeval_best');
        }
        $mform->addElement('select', 'comparison', get_string('comparison', 'workshopeval_best'), $options);
        $mform->addHelpButton('comparison', 'comparison', 'workshopeval_best');
        $mform->setDefault('comparison', $plugindefaults->comparison);

        $this->set_data($current);
    }