Search moodle.org's
Developer Documentation

See Release Notes

  • Bug fixes for general core bugs in 3.10.x will end 8 November 2021 (12 months).
  • Bug fixes for security issues in 3.10.x will end 9 May 2022 (18 months).
  • PHP version: minimum PHP 7.2.0 Note: minimum PHP version has increased since Moodle 3.8. PHP 7.3.x and 7.4.x are supported too.
<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**
 * Quiz statistics report, table for showing statistics of each question in the quiz.
 *
 * @package   quiz_statistics
 * @copyright 2008 Jamie Pratt
 * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */

defined('MOODLE_INTERNAL') || die();

require_once($CFG->libdir.'/tablelib.php');

use \core_question\statistics\questions\calculated_question_summary;

/**
 * This table has one row for each question in the quiz, with sub-rows when
 * random questions and variants appear.
 *
 * There are columns for the various item and position statistics.
 *
 * @copyright 2008 Jamie Pratt
 * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */
class quiz_statistics_table extends flexible_table {
    /** @var object the quiz settings. */
    protected $quiz;

    /** @var integer the quiz course_module id. */
    protected $cmid;

    /**
     * Constructor.
     */
    public function __construct() {
        parent::__construct('mod-quiz-report-statistics-report');
    }

    /**
     * Set up the columns and headers and other properties of the table and then
     * call flexible_table::setup() method.
     *
     * @param object $quiz the quiz settings
     * @param int $cmid the quiz course_module id
     * @param moodle_url $reporturl the URL to redisplay this report.
     * @param int $s number of attempts included in the statistics.
     */
    public function statistics_setup($quiz, $cmid, $reporturl, $s) {
        $this->quiz = $quiz;
        $this->cmid = $cmid;

        // Define the table columns.
        $columns = array();
        $headers = array();

        $columns[] = 'number';
        $headers[] = get_string('questionnumber', 'quiz_statistics');

        if (!$this->is_downloading()) {
            $columns[] = 'icon';
            $headers[] = '';
            $columns[] = 'actions';
            $headers[] = '';
        } else {
            $columns[] = 'qtype';
            $headers[] = get_string('questiontype', 'quiz_statistics');
        }

        $columns[] = 'name';
        $headers[] = get_string('questionname', 'quiz');

        $columns[] = 's';
        $headers[] = get_string('attempts', 'quiz_statistics');

        if ($s > 1) {
            $columns[] = 'facility';
            $headers[] = get_string('facility', 'quiz_statistics');

            $columns[] = 'sd';
            $headers[] = get_string('standarddeviationq', 'quiz_statistics');
        }

        $columns[] = 'random_guess_score';
        $headers[] = get_string('random_guess_score', 'quiz_statistics');

        $columns[] = 'intended_weight';
        $headers[] = get_string('intended_weight', 'quiz_statistics');

        $columns[] = 'effective_weight';
        $headers[] = get_string('effective_weight', 'quiz_statistics');

        $columns[] = 'discrimination_index';
        $headers[] = get_string('discrimination_index', 'quiz_statistics');

        $columns[] = 'discriminative_efficiency';
        $headers[] = get_string('discriminative_efficiency', 'quiz_statistics');

        $this->define_columns($columns);
        $this->define_headers($headers);
        $this->sortable(false);

        $this->column_class('s', 'numcol');
        $this->column_class('facility', 'numcol');
        $this->column_class('sd', 'numcol');
        $this->column_class('random_guess_score', 'numcol');
        $this->column_class('intended_weight', 'numcol');
        $this->column_class('effective_weight', 'numcol');
        $this->column_class('discrimination_index', 'numcol');
        $this->column_class('discriminative_efficiency', 'numcol');

        // Set up the table.
        $this->define_baseurl($reporturl->out());

        $this->collapsible(true);

        $this->set_attribute('id', 'questionstatistics');
        $this->set_attribute('class', 'generaltable generalbox boxaligncenter');

        parent::setup();
    }

    /**
     * Open a div tag to wrap statistics table.
     */
    public function  wrap_html_start() {
        // Horrible Moodle 2.0 wide-content work-around.
        if (!$this->is_downloading()) {
            echo html_writer::start_tag('div', array('id' => 'tablecontainer',
                    'class' => 'statistics-tablecontainer'));
        }
    }

    /**
     * Close a statistics table div.
     */
    public function wrap_html_finish() {
        if (!$this->is_downloading()) {
            echo html_writer::end_tag('div');
        }
    }

    /**
     * The question number.
     * @param \core_question\statistics\questions\calculated $questionstat stats for the question.
     * @return string contents of this table cell.
     */
    protected function col_number($questionstat) {
        if ($this->is_calculated_question_summary($questionstat)) {
            return '';
        }
        if (!isset($questionstat->question->number)) {
            return '';
        }
        $number = $questionstat->question->number;

        if (isset($questionstat->subqdisplayorder)) {
            $number = $number . '.'.$questionstat->subqdisplayorder;
        }

        if ($questionstat->question->qtype != 'random' && !is_null($questionstat->variant)) {
            $number = $number . '.'.$questionstat->variant;
        }

        return $number;
    }

    /**
     * The question type icon.
     * @param \core_question\statistics\questions\calculated $questionstat stats for the question.
     * @return string contents of this table cell.
     */
    protected function col_icon($questionstat) {
        if ($this->is_calculated_question_summary($questionstat)) {
            return '';
        } else {
< return print_question_icon($questionstat->question, true);
> $questionobject = $questionstat->question; > return print_question_icon($questionobject);
} } /** * Actions that can be performed on the question by this user (e.g. edit or preview). * @param \core_question\statistics\questions\calculated $questionstat stats for the question. * @return string contents of this table cell. */ protected function col_actions($questionstat) { if ($this->is_calculated_question_summary($questionstat)) {
> return ''; return ''; > } else if ($questionstat->question->qtype === 'missingtype') {
} else { return quiz_question_action_icons($this->quiz, $this->cmid, $questionstat->question, $this->baseurl, $questionstat->variant); } } /** * The question type name. * * @param \core_question\statistics\questions\calculated $questionstat stats for the question. * @return string contents of this table cell. */ protected function col_qtype($questionstat) { return question_bank::get_qtype_name($questionstat->question->qtype); } /** * The question name. * * @param \core_question\statistics\questions\calculated $questionstat stats for the question. * @return string contents of this table cell. */ protected function col_name($questionstat) { $name = $questionstat->question->name; if (!is_null($questionstat->variant)) { $a = new stdClass(); $a->name = $name; $a->variant = $questionstat->variant; $name = get_string('nameforvariant', 'quiz_statistics', $a); } if ($this->is_downloading()) { return $name; } $baseurl = new moodle_url($this->baseurl); if (!is_null($questionstat->variant)) { if ($questionstat->subquestion) { // Variant of a sub-question. $url = new moodle_url($baseurl, array('qid' => $questionstat->questionid, 'variant' => $questionstat->variant)); $name = html_writer::link($url, $name, array('title' => get_string('detailedanalysisforvariant', 'quiz_statistics', $questionstat->variant))); } else if ($questionstat->slot) { // Variant of a question in a slot. $url = new moodle_url($baseurl, array('slot' => $questionstat->slot, 'variant' => $questionstat->variant)); $name = html_writer::link($url, $name, array('title' => get_string('detailedanalysisforvariant', 'quiz_statistics', $questionstat->variant))); } } else { if ($questionstat->subquestion && !$questionstat->get_variants()) { // Sub question without variants. $url = new moodle_url($baseurl, array('qid' => $questionstat->questionid)); $name = html_writer::link($url, $name, array('title' => get_string('detailedanalysis', 'quiz_statistics'))); } else if ($baseurl->param('slot') === null && $questionstat->slot) { // Question in a slot, we are not on a page showing structural analysis of one slot, // we don't want linking on those pages. $number = $questionstat->question->number; $israndomquestion = $questionstat->question->qtype == 'random'; $url = new moodle_url($baseurl, array('slot' => $questionstat->slot)); if ($this->is_calculated_question_summary($questionstat)) { // Only make the random question summary row name link to the slot structure // analysis page with specific text to clearly indicate the link to the user. // Random and variant question rows will render the name without a link to improve clarity // in the UI. $name = html_writer::div(get_string('rangeofvalues', 'quiz_statistics')); } else if (!$israndomquestion && !$questionstat->get_variants() && !$questionstat->get_sub_question_ids()) { // Question cannot be broken down into sub-questions or variants. Link will show response analysis page. $name = html_writer::link($url, $name, array('title' => get_string('detailedanalysis', 'quiz_statistics'))); } } } if ($this->is_dubious_question($questionstat)) { $name = html_writer::tag('div', $name, array('class' => 'dubious')); } if ($this->is_calculated_question_summary($questionstat)) { $name .= html_writer::link($url, get_string('viewanalysis', 'quiz_statistics')); } else if (!empty($questionstat->minmedianmaxnotice)) { $name = get_string($questionstat->minmedianmaxnotice, 'quiz_statistics') . '<br />' . $name; } return $name; } /** * The number of attempts at this question. * * @param \core_question\statistics\questions\calculated $questionstat stats for the question. * @return string contents of this table cell. */ protected function col_s($questionstat) { if ($this->is_calculated_question_summary($questionstat)) { list($min, $max) = $questionstat->get_min_max_of('s'); $min = $min ?: 0; $max = $max ?: 0; return $this->format_range($min, $max); } else if (!isset($questionstat->s)) { return 0; } else { return $questionstat->s; } } /** * The facility index (average fraction). * @param \core_question\statistics\questions\calculated $questionstat stats for the question. * @return string contents of this table cell. */ protected function col_facility($questionstat) { if ($this->is_calculated_question_summary($questionstat)) { list($min, $max) = $questionstat->get_min_max_of('facility'); return $this->format_percentage_range($min, $max); } else if (is_null($questionstat->facility)) { return ''; } else { return $this->format_percentage($questionstat->facility); } } /** * The standard deviation of the fractions. * @param \core_question\statistics\questions\calculated $questionstat stats for the question. * @return string contents of this table cell. */ protected function col_sd($questionstat) { if ($this->is_calculated_question_summary($questionstat)) { list($min, $max) = $questionstat->get_min_max_of('sd'); return $this->format_percentage_range($min, $max); } else if (is_null($questionstat->sd) || $questionstat->maxmark == 0) { return ''; } else { return $this->format_percentage($questionstat->sd / $questionstat->maxmark); } } /** * An estimate of the fraction a student would get by guessing randomly. * @param \core_question\statistics\questions\calculated $questionstat stats for the question. * @return string contents of this table cell. */ protected function col_random_guess_score($questionstat) { if ($this->is_calculated_question_summary($questionstat)) { list($min, $max) = $questionstat->get_min_max_of('randomguessscore'); return $this->format_percentage_range($min, $max); } else if (is_null($questionstat->randomguessscore)) { return ''; } else { return $this->format_percentage($questionstat->randomguessscore); } } /** * The intended question weight. Maximum mark for the question as a percentage * of maximum mark for the quiz. That is, the indended influence this question * on the student's overall mark. * @param \core_question\statistics\questions\calculated $questionstat stats for the question. * @return string contents of this table cell. */ protected function col_intended_weight($questionstat) { if ($this->is_calculated_question_summary($questionstat)) { list($min, $max) = $questionstat->get_min_max_of('maxmark'); if (is_null($min) && is_null($max)) { return ''; } else { $min = quiz_report_scale_summarks_as_percentage($min, $this->quiz); $max = quiz_report_scale_summarks_as_percentage($max, $this->quiz); return $this->format_range($min, $max); } } else { return quiz_report_scale_summarks_as_percentage($questionstat->maxmark, $this->quiz); } } /** * The effective question weight. That is, an estimate of the actual * influence this question has on the student's overall mark. * @param \core_question\statistics\questions\calculated $questionstat stats for the question. * @return string contents of this table cell. */ protected function col_effective_weight($questionstat) { global $OUTPUT; if ($this->is_calculated_question_summary($questionstat)) { list($min, $max) = $questionstat->get_min_max_of('effectiveweight'); if (is_null($min) && is_null($max)) { return ''; } else { list( , $negcovar) = $questionstat->get_min_max_of('negcovar'); if ($negcovar) { $min = get_string('negcovar', 'quiz_statistics'); } return $this->format_range($min, $max); } } else if (is_null($questionstat->effectiveweight)) { return ''; } else if ($questionstat->negcovar) { $negcovar = get_string('negcovar', 'quiz_statistics'); if (!$this->is_downloading()) { $negcovar = html_writer::tag('div', $negcovar . $OUTPUT->help_icon('negcovar', 'quiz_statistics'), array('class' => 'negcovar')); } return $negcovar; } else { return $this->format_percentage($questionstat->effectiveweight, false); } } /** * Discrimination index. This is the product moment correlation coefficient * between the fraction for this question, and the average fraction for the * other questions in this quiz. * @param \core_question\statistics\questions\calculated $questionstat stats for the question. * @return string contents of this table cell. */ protected function col_discrimination_index($questionstat) { if ($this->is_calculated_question_summary($questionstat)) { list($min, $max) = $questionstat->get_min_max_of('discriminationindex'); if (isset($max)) { $min = $min ?: 0; } if (is_numeric($min)) { $min = $this->format_percentage($min, false); } if (is_numeric($max)) { $max = $this->format_percentage($max, false); } return $this->format_range($min, $max); } else if (!is_numeric($questionstat->discriminationindex)) { return $questionstat->discriminationindex; } else { return $this->format_percentage($questionstat->discriminationindex, false); } } /** * Discrimination efficiency, similar to, but different from, the Discrimination index. * * @param \core_question\statistics\questions\calculated $questionstat stats for the question. * @return string contents of this table cell. */ protected function col_discriminative_efficiency($questionstat) { if ($this->is_calculated_question_summary($questionstat)) { list($min, $max) = $questionstat->get_min_max_of('discriminativeefficiency'); if (!is_numeric($min) && !is_numeric($max)) { return ''; } else { return $this->format_percentage_range($min, $max, false); } } else if (!is_numeric($questionstat->discriminativeefficiency)) { return ''; } else { return $this->format_percentage($questionstat->discriminativeefficiency, false); } } /** * This method encapsulates the test for wheter a question should be considered dubious. * @param \core_question\statistics\questions\calculated $questionstat stats for the question. * @return bool is this question possibly not pulling it's weight? */ protected function is_dubious_question($questionstat) { if ($this->is_calculated_question_summary($questionstat)) { // We only care about the minimum value here. // If the minimum value is less than the threshold, then we know that there is at least one value below the threshold. list($discriminativeefficiency) = $questionstat->get_min_max_of('discriminativeefficiency'); } else { $discriminativeefficiency = $questionstat->discriminativeefficiency; } if (!is_numeric($discriminativeefficiency)) { return false; } return $discriminativeefficiency < 15; } /** * Check if the given stats object is an instance of calculated_question_summary. * * @param \core_question\statistics\questions\calculated $questionstat Stats object * @return bool */ protected function is_calculated_question_summary($questionstat) { return $questionstat instanceof calculated_question_summary; } /** * Format inputs to represent a range between $min and $max. * This function does not check if $min is less than $max or not. * If both $min and $max are equal to null, this function returns an empty string. * * @param string|null $min The minimum value in the range * @param string|null $max The maximum value in the range * @return string */ protected function format_range(string $min = null, string $max = null) { if (is_null($min) && is_null($max)) { return ''; } else { $a = new stdClass(); $a->min = $min; $a->max = $max; return get_string('rangebetween', 'quiz_statistics', $a); } } /** * Format a number to a localised percentage with specified decimal points. * * @param float $number The number being formatted * @param bool $fraction An indicator for whether the number is a fraction or is already multiplied by 100 * @param int $decimals Sets the number of decimal points * @return string */ protected function format_percentage(float $number, bool $fraction = true, int $decimals = 2) { $coefficient = $fraction ? 100 : 1; return get_string('percents', 'moodle', format_float($number * $coefficient, $decimals)); } /** * Format $min and $max to localised percentages and form a string that represents a range between them. * This function does not check if $min is less than $max or not. * If both $min and $max are equal to null, this function returns an empty string. * * @param float|null $min The minimum value of the range * @param float|null $max The maximum value of the range * @param bool $fraction An indicator for whether min and max are a fractions or are already multiplied by 100 * @param int $decimals Sets the number of decimal points * @return string A formatted string that represents a range between $min to $max. */ protected function format_percentage_range(float $min = null, float $max = null, bool $fraction = true, int $decimals = 2) { if (is_null($min) && is_null($max)) { return ''; } else { $min = $min ?: 0; $max = $max ?: 0; return $this->format_range( $this->format_percentage($min, $fraction, $decimals), $this->format_percentage($max, $fraction, $decimals) ); } } }