<?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 stdClass 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 stdClass $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 = [];
$headers = [];
$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', ['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 {
$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 '';
} else if ($questionstat->question->qtype === 'missingtype') {
return '';
} else {
return quiz_question_action_icons($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, ['qid' => $questionstat->questionid, 'variant' => $questionstat->variant]);
$name = html_writer::link($url, $name, ['title' => get_string('detailedanalysisforvariant',
'quiz_statistics',
$questionstat->variant)]);
} else if ($questionstat->slot) {
// Variant of a question in a slot.
$url = new moodle_url($baseurl, ['slot' => $questionstat->slot, 'variant' => $questionstat->variant]);
$name = html_writer::link($url, $name, ['title' => get_string('detailedanalysisforvariant',
'quiz_statistics',
$questionstat->variant)]);
}
} else {
if ($questionstat->subquestion && !$questionstat->get_variants()) {
// Sub question without variants.
$url = new moodle_url($baseurl, ['qid' => $questionstat->questionid]);
$name = html_writer::link($url, $name, ['title' => get_string('detailedanalysis', 'quiz_statistics')]);
} else if ($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, ['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,
$name,
['title' => get_string('detailedanalysis', 'quiz_statistics')]);
}
}
}
if ($this->is_dubious_question($questionstat)) {
$name = html_writer::tag('div', $name, ['class' => 'dubious']);
}
if ($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'),
['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)
);
}
}
}