diff --git a/lib/completion/completion_aggregation.php b/lib/completion/completion_aggregation.php
index 627f9625293..e7a07863781 100644
--- a/lib/completion/completion_aggregation.php
+++ b/lib/completion/completion_aggregation.php
@@ -39,10 +39,7 @@ require_once($CFG->libdir.'/completion/data_object.php');
  */
 class completion_aggregation extends data_object {
 
-    /**
-     * Database table name that stores completion aggregation information
-     * @var string
-     */
+    /* @var string Database table name that stores completion aggregation information */
     public $table = 'course_completion_aggr_methd';
 
     /**
@@ -52,28 +49,16 @@ class completion_aggregation extends data_object {
      */
     public $required_fields = array('id', 'course', 'criteriatype', 'method', 'value');
 
-    /**
-     * Course id
-     * @var int
-     */
+    /* @var int Course id */
     public $course;
 
-    /**
-     * Criteria type this aggregation method applies to, or NULL for overall course aggregation
-     * @var int
-     */
+    /* @var int Criteria type this aggregation method applies to, or NULL for overall course aggregation */
     public $criteriatype;
 
-    /**
-     * Aggregation method (COMPLETION_AGGREGATION_* constant)
-     * @var int
-     */
+    /* @var int Aggregation method (COMPLETION_AGGREGATION_* constant)*/
     public $method;
 
-    /**
-     * Method value
-     * @var mixed
-     */
+    /* @var mixed Method value */
     public $value;
 
 
@@ -113,4 +98,4 @@ class completion_aggregation extends data_object {
             $this->method = COMPLETION_AGGREGATION_ALL;
         }
     }
-}
\ No newline at end of file
+}
diff --git a/lib/completion/completion_completion.php b/lib/completion/completion_completion.php
index bb6e107c18c..f744a97aa57 100644
--- a/lib/completion/completion_completion.php
+++ b/lib/completion/completion_completion.php
@@ -38,47 +38,26 @@ require_once($CFG->libdir.'/completion/data_object.php');
  */
 class completion_completion extends data_object {
 
-    /**
-     * Database table name that stores completion information
-     * @var string $table
-     */
+    /* @var string $table Database table name that stores completion information */
     public $table = 'course_completions';
 
-    /**
-     * Array of required table fields, must start with 'id'.
-     * @var array $required_fields
-     */
+    /* @var array $required_fields Array of required table fields, must start with 'id'. */
     public $required_fields = array('id', 'userid', 'course', 'deleted', 'timenotified',
         'timeenrolled', 'timestarted', 'timecompleted', 'reaggregate');
 
-    /**
-     * User ID
-     * @var int
-     */
+    /* @var int $userid User ID */
     public $userid;
 
-    /**
-     * Course ID
-     * @var int
-     */
+    /* @var int $course Course ID */
     public $course;
 
-    /**
-     * Set to 1 if this record has been deleted
-     * @var int
-     */
+    /* @var int $deleted set to 1 if this record has been deleted */
     public $deleted;
 
-    /**
-     * Timestamp the interested parties were notified of this user's completion.
-     * @var int
-     */
+    /* @var int Timestamp the interested parties were notified of this user's completion. */
     public $timenotified;
 
-    /**
-     * Time of course enrolment {@see completion_completion::mark_enrolled()}
-     * @var int
-     */
+    /* @var int Time of course enrolment {@see completion_completion::mark_enrolled()} */
     public $timeenrolled;
 
     /**
@@ -87,22 +66,16 @@ class completion_completion extends data_object {
      */
     public $timestarted;
 
-    /**
-     * Timestamp of course completion {@see completion_completion::mark_complete()}
-     * @var int
-     */
+    /* @var int Timestamp of course completion {@see completion_completion::mark_complete()} */
     public $timecompleted;
 
-    /**
-     * Flag to trigger cron aggregation (timestamp)
-     * @var int
-     */
+    /* @var int Flag to trigger cron aggregation (timestamp) */
     public $reaggregate;
 
 
     /**
      * Finds and returns a data_object instance based on params.
-     * 
+     *
      * @param array $params associative arrays varname = >value
      * @return data_object instance of data_object or false if none found.
      */
@@ -114,7 +87,7 @@ class completion_completion extends data_object {
     /**
      * Return status of this completion
      *
-     * @return boolean
+     * @return bool
      */
     public function is_complete() {
         return (bool) $this->timecompleted;
@@ -224,4 +197,4 @@ class completion_completion extends data_object {
             $this->insert();
         }
     }
-}
\ No newline at end of file
+}
diff --git a/lib/completion/completion_criteria.php b/lib/completion/completion_criteria.php
index 6d6cc172950..d93e9a043a2 100644
--- a/lib/completion/completion_criteria.php
+++ b/lib/completion/completion_criteria.php
@@ -103,10 +103,7 @@ $COMPLETION_CRITERIA_TYPES = array(
  */
 abstract class completion_criteria extends data_object {
 
-    /**
-     * Database table name that stores completion criteria information
-     * @var string
-     */
+    /* @var string Database table name that stores completion criteria information  */
     public $table = 'course_completion_criteria';
 
     /**
@@ -117,10 +114,7 @@ abstract class completion_criteria extends data_object {
      */
     public $required_fields = array('id', 'course', 'criteriatype', 'module', 'moduleinstance', 'courseinstance', 'enrolperiod', 'timeend', 'gradepass', 'role');
 
-    /**
-     * Course id
-     * @var int
-     */
+    /* @var int Course id  */
     public $course;
 
     /**
@@ -130,16 +124,10 @@ abstract class completion_criteria extends data_object {
      */
     public $criteriatype;
 
-    /**
-     * Module type this criteria relates to (for activity criteria)
-     * @var string
-     */
+    /* @var string Module type this criteria relates to (for activity criteria)  */
     public $module;
 
-    /**
-     * Course module instance id this criteria relates to (for activity criteria)
-     * @var int
-     */
+    /* @var int Course module instance id this criteria relates to (for activity criteria) */
     public $moduleinstance;
 
     /**
@@ -156,16 +144,10 @@ abstract class completion_criteria extends data_object {
      */
     public $date;
 
-    /**
-     * Passing grade required to complete course (for grade completion)
-     * @var float
-     */
+    /* @var float Passing grade required to complete course (for grade completion) */
     public $gradepass;
 
-    /**
-     * Role ID that has the ability to mark a user as complete (for role completion)
-     * @var int
-     */
+    /* @var int Role ID that has the ability to mark a user as complete (for role completion) */
     public $role;
 
     /**
@@ -197,9 +179,9 @@ abstract class completion_criteria extends data_object {
 
     /**
      * Add appropriate form elements to the critieria form
-     * 
+     *
      * @param moodleform $mform Moodle forms object
-     * @param mixed $data optional
+     * @param mixed $data optional Any additional data that can be used to set default values in the form
      * @return void
      */
     abstract public function config_form_display(&$mform, $data = null);
@@ -272,4 +254,4 @@ abstract class completion_criteria extends data_object {
 
         return $review !== $completion->is_complete();
     }
-}
\ No newline at end of file
+}
diff --git a/lib/completion/completion_criteria_activity.php b/lib/completion/completion_criteria_activity.php
index 76b182ac795..409bf42c08f 100644
--- a/lib/completion/completion_criteria_activity.php
+++ b/lib/completion/completion_criteria_activity.php
@@ -39,10 +39,7 @@ defined('MOODLE_INTERNAL') || die();
  */
 class completion_criteria_activity extends completion_criteria {
 
-    /**
-     * Criteria type constant
-     * @var int [COMPLETION_CRITERIA_TYPE_ACTIVITY]
-     */
+    /* @var int Criteria [COMPLETION_CRITERIA_TYPE_ACTIVITY] */
     public $criteriatype = COMPLETION_CRITERIA_TYPE_ACTIVITY;
 
     /**
@@ -58,9 +55,9 @@ class completion_criteria_activity extends completion_criteria {
 
     /**
      * Add appropriate form elements to the critieria form
-     * 
+     *
      * @param moodleform $mform  Moodle forms object
-     * @param stdClass $data
+     * @param stdClass $data details of various modules
      */
     public function config_form_display(&$mform, $data = null) {
         $mform->addElement('checkbox', 'criteria_activity['.$data->id.']', ucfirst(self::get_mod_name($data->module)).' - '.$data->name);
@@ -72,7 +69,7 @@ class completion_criteria_activity extends completion_criteria {
 
     /**
      * Update the criteria information stored in the database
-     * 
+     *
      * @param stdClass $data Form data
      */
     public function update_config(&$data) {
@@ -95,7 +92,7 @@ class completion_criteria_activity extends completion_criteria {
 
     /**
      * Get module instance module type
-     * 
+     *
      * @param int $type Module type id
      * @return string
      */
@@ -114,7 +111,7 @@ class completion_criteria_activity extends completion_criteria {
      * Gets the module instance from the database and returns it.
      * If no module instance exists this function returns false.
      *
-     * @return stdClass|false
+     * @return stdClass|bool
      */
     public function get_mod_instance() {
         global $DB;
@@ -137,8 +134,8 @@ class completion_criteria_activity extends completion_criteria {
      * Review this criteria and decide if the user has completed
      *
      * @param completion_completion $completion     The user's completion record
-     * @param boolean $mark Optionally set false to not save changes to database
-     * @return boolean
+     * @param bool $mark Optionally set false to not save changes to database
+     * @return bool
      */
     public function review($completion, $mark = true) {
         global $DB;
@@ -193,7 +190,7 @@ class completion_criteria_activity extends completion_criteria {
     }
 
     /**
-     * Find user's who have completed this criteria and mark them accordingly
+     * Find users who have completed this criteria and mark them accordingly
      */
     public function cron() {
         global $DB;
@@ -290,4 +287,4 @@ class completion_criteria_activity extends completion_criteria {
 
         return $details;
     }
-}\
\ No newline at end of file
+}
diff --git a/lib/completion/completion_criteria_completion.php b/lib/completion/completion_criteria_completion.php
index e016ebdda60..10e54d0781b 100644
--- a/lib/completion/completion_criteria_completion.php
+++ b/lib/completion/completion_criteria_completion.php
@@ -38,70 +38,37 @@ require_once($CFG->libdir.'/completion/data_object.php');
  */
 class completion_criteria_completion extends data_object {
 
-    /**
-     * Database table that stores completion type criteria
-     * @var string
-     */
+    /* @var string Database table that stores completion type criteria */
     public $table = 'course_completion_crit_compl';
 
-    /**
-     * Array of required table fields, must start with 'id'.
-     * @var array
-     */
+    /* @var array Array of required table fields, must start with 'id'. */
     public $required_fields = array('id', 'userid', 'course', 'criteriaid', 'gradefinal', 'rpl', 'deleted', 'unenroled', 'timecompleted');
 
-    /**
-     * User ID
-     * @var int
-     */
+    /* @var int User ID */
     public $userid;
 
-    /**
-     * Course ID
-     * @var int
-     */
+    /* @var int course ID */
     public $course;
 
-    /**
-     * The id of the course completion criteria this completion references
-     * @var int
-     */
+    /* @var int The id of the course completion criteria this completion references */
     public $criteriaid;
 
-    /**
-     * The final grade for the user in the course (if completing a grade criteria)
-     * @var float
-     */
+    /* @var float The final grade for the user in the course (if completing a grade criteria) */
     public $gradefinal;
 
-    /**
-     * Record of prior learning, leave blank if none
-     * @var string
-     */
+    /* @var string Record of prior learning, leave blank if none */
     public $rpl;
 
-    /**
-     * Course deleted flag
-     * @var boolean
-     */
+    /* @var bool Course deleted flag */
     public $deleted;
 
-    /**
-     * Timestamp of user unenrolment (if completing a unenrol criteria)
-     * @var int
-     */
+    /* @var int Timestamp of user unenrolment (if completing a unenrol criteria) */
     public $unenroled;
 
-    /**
-     * Timestamp of course criteria completion {@see completion_criteria_completion::mark_complete()}
-     * @var int
-     */
+    /* @var int Timestamp of course criteria completion {@see completion_criteria_completion::mark_complete()} */
     public $timecompleted;
 
-    /**
-     * Associated criteria object
-     * @var completion_criteria
-     */
+    /* @var completion_criterria Associated criteria object */
     private $_criteria;
 
     /**
@@ -125,7 +92,8 @@ class completion_criteria_completion extends data_object {
 
     /**
      * Return status of this criteria completion
-     * @return boolean
+     *
+     * @return bool
      */
     public function is_complete() {
         return (bool) $this->timecompleted;
@@ -158,7 +126,7 @@ class completion_criteria_completion extends data_object {
 
     /**
      * Attach a preloaded criteria object to this object
-     * 
+     *
      * @param   $criteria   object  completion_criteria
      */
     public function attach_criteria(completion_criteria $criteria) {
@@ -168,12 +136,13 @@ class completion_criteria_completion extends data_object {
     /**
      * Return the associated criteria with this completion
      * If nothing attached, load from the db
-     * 
+     *
      * @return completion_criteria
      */
     public function get_criteria() {
 
-        if (!$this->_criteria) {
+        if (!$this->_criteria) 
+        {
             global $DB;
 
             $params = array(
@@ -190,6 +159,7 @@ class completion_criteria_completion extends data_object {
 
     /**
      * Return criteria status text for display in reports {@see completion_criteria::get_status()}
+     *
      * @return string
      */
     public function get_status() {
diff --git a/lib/completion/completion_criteria_course.php b/lib/completion/completion_criteria_course.php
index e7f019fd52e..882ee6365c2 100644
--- a/lib/completion/completion_criteria_course.php
+++ b/lib/completion/completion_criteria_course.php
@@ -40,10 +40,7 @@ defined('MOODLE_INTERNAL') || die();
  */
 class completion_criteria_course extends completion_criteria {
 
-    /**
-     * Criteria type constant
-     * @var int
-     */
+    /* @var int Criteria type constant */
     public $criteriatype = COMPLETION_CRITERIA_TYPE_COURSE;
 
     /**
@@ -61,7 +58,7 @@ class completion_criteria_course extends completion_criteria {
      * Add appropriate form elements to the critieria form
      *
      * @param moodle_form $mform Moodle forms object
-     * @param stdClass $data
+     * @param stdClass $data data used to define default value of the form
      */
     public function config_form_display(&$mform, $data = null) {
         global $CFG;
@@ -98,8 +95,8 @@ class completion_criteria_course extends completion_criteria {
      * Review this criteria and decide if the user has completed
      *
      * @param completion_completion $completion The user's completion record
-     * @param boolean $mark Optionally set false to not save changes to database
-     * @return boolean
+     * @param bool $mark Optionally set false to not save changes to database
+     * @return bool
      */
     public function review($completion, $mark = true) {
         global $DB;
@@ -131,7 +128,7 @@ class completion_criteria_course extends completion_criteria {
 
     /**
      * Return a more detailed criteria title for display in reports
-     * 
+     *
      * @return string
      */
     public function get_title_detailed() {
diff --git a/lib/completion/completion_criteria_date.php b/lib/completion/completion_criteria_date.php
index 318c0513af8..e6e81c09148 100644
--- a/lib/completion/completion_criteria_date.php
+++ b/lib/completion/completion_criteria_date.php
@@ -37,10 +37,7 @@ defined('MOODLE_INTERNAL') || die();
  */
 class completion_criteria_date extends completion_criteria {
 
-    /**
-     * Criteria type constant [COMPLETION_CRITERIA_TYPE_DATE]
-     * @var int
-     */
+    /* @var int Criteria type constant [COMPLETION_CRITERIA_TYPE_DATE]  */
     public $criteriatype = COMPLETION_CRITERIA_TYPE_DATE;
 
     /**
@@ -58,7 +55,7 @@ class completion_criteria_date extends completion_criteria {
      * Add appropriate form elements to the critieria form
      *
      * @param moodleform $mform Moodle forms object
-     * @param stdClass $data
+     * @param stdClass $data not used
      */
     public function config_form_display(&$mform, $data = null) {
         $mform->addElement('checkbox', 'criteria_date', get_string('enable'));
@@ -88,10 +85,10 @@ class completion_criteria_date extends completion_criteria {
 
     /**
      * Review this criteria and decide if the user has completed
-     * 
+     *
      * @param completion_completion $completion The user's completion record
-     * @param boolean $mark Optionally set false to not save changes to database
-     * @return boolean
+     * @param bool $mark Optionally set false to not save changes to database
+     * @return bool
      */
     public function review($completion, $mark = true) {
         // If current time is past timeend
diff --git a/lib/completion/completion_criteria_duration.php b/lib/completion/completion_criteria_duration.php
index a3045fce9ff..97bcb923b00 100644
--- a/lib/completion/completion_criteria_duration.php
+++ b/lib/completion/completion_criteria_duration.php
@@ -37,10 +37,7 @@ defined('MOODLE_INTERNAL') || die();
  */
 class completion_criteria_duration extends completion_criteria {
 
-    /**
-     * Criteria type constant [COMPLETION_CRITERIA_TYPE_DURATION]
-     * @var int
-     */
+    /* @var int Criteria type constant [COMPLETION_CRITERIA_TYPE_DURATION] */
     public $criteriatype = COMPLETION_CRITERIA_TYPE_DURATION;
 
     /**
@@ -58,7 +55,7 @@ class completion_criteria_duration extends completion_criteria {
      * Add appropriate form elements to the critieria form
      *
      * @param moodleform $mform Moodle forms object
-     * @param stdClass $data
+     * @param stdClass $data not used
      */
     public function config_form_display(&$mform, $data = null) {
 
@@ -111,8 +108,8 @@ class completion_criteria_duration extends completion_criteria {
      * Review this criteria and decide if the user has completed
      *
      * @param completion_completion $completion The user's completion record
-     * @param boolean $mark Optionally set false to not save changes to database
-     * @return boolean
+     * @param bool $mark Optionally set false to not save changes to database
+     * @return bool
      */
     public function review($completion, $mark = true) {
         $timeenrolled = $this->get_timeenrolled($completion);
@@ -265,4 +262,4 @@ class completion_criteria_duration extends completion_criteria {
 
         return $details;
     }
-}
\ No newline at end of file
+}
diff --git a/lib/completion/completion_criteria_grade.php b/lib/completion/completion_criteria_grade.php
index c9fd54a5c3f..e452454d080 100644
--- a/lib/completion/completion_criteria_grade.php
+++ b/lib/completion/completion_criteria_grade.php
@@ -39,16 +39,14 @@ require_once $CFG->dirroot.'/grade/querylib.php';
  */
 class completion_criteria_grade extends completion_criteria {
 
-    /**
-     * Criteria type constant [COMPLETION_CRITERIA_TYPE_GRADE]
-     * @var int
-     */
+    /* @var int Criteria type constant [COMPLETION_CRITERIA_TYPE_GRADE] */
     public $criteriatype = COMPLETION_CRITERIA_TYPE_GRADE;
 
     /**
      * Finds and returns a data_object instance based on params.
      *
-     * @param array $params associative arrays varname => value
+     * @param array $params associative array varname => value of various 
+     * parameters used to fetch data_object
      * @return data_object data_object instance or false if none found.
      */
     public static function fetch($params) {
@@ -60,7 +58,7 @@ class completion_criteria_grade extends completion_criteria {
      * Add appropriate form elements to the critieria form
      *
      * @param moodle_form $mform Moodle forms object
-     * @param stdClass $data
+     * @param stdClass $data containing default values to be set in the form
      */
     public function config_form_display(&$mform, $data = null) {
         $mform->addElement('checkbox', 'criteria_grade', get_string('enable'));
@@ -79,7 +77,10 @@ class completion_criteria_grade extends completion_criteria {
      * @param stdClass $data Form data
      */
     public function update_config(&$data) {
-        if (!empty($data->criteria_grade) && is_numeric($data->criteria_grade_value)) {
+
+        // TODO validation
+        if (!empty($data->criteria_grade) && is_numeric($data->criteria_grade_value))
+        {
             $this->course = $data->id;
             $this->gradepass = $data->criteria_grade_value;
             $this->insert();
@@ -88,8 +89,8 @@ class completion_criteria_grade extends completion_criteria {
 
     /**
      * Get user's course grade in this course
-     * 
-     * @param completion_completion $completion
+     *
+     * @param completion_completion $completion an instance of completion_completion class
      * @return float
      */
     private function get_grade($completion) {
@@ -101,8 +102,8 @@ class completion_criteria_grade extends completion_criteria {
      * Review this criteria and decide if the user has completed
      *
      * @param completion_completion $completion The user's completion record
-     * @param boolean $mark Optionally set false to not save changes to database
-     * @return boolean
+     * @param bool $mark Optionally set false to not save changes to database
+     * @return bool
      */
     public function review($completion, $mark = true) {
         // Get user's course grade
@@ -241,4 +242,4 @@ class completion_criteria_grade extends completion_criteria {
 
         return $details;
     }
-}
\ No newline at end of file
+}
diff --git a/lib/completion/completion_criteria_role.php b/lib/completion/completion_criteria_role.php
index dd8c4319215..0eeb462b154 100644
--- a/lib/completion/completion_criteria_role.php
+++ b/lib/completion/completion_criteria_role.php
@@ -37,10 +37,7 @@ defined('MOODLE_INTERNAL') || die();
  */
 class completion_criteria_role extends completion_criteria {
 
-    /**
-     * Criteria type constant [COMPLETION_CRITERIA_TYPE_ROLE]
-     * @var int
-     */
+    /* @var int Criteria type constant [COMPLETION_CRITERIA_TYPE_ROLE] */
     public $criteriatype = COMPLETION_CRITERIA_TYPE_ROLE;
 
     /**
@@ -56,9 +53,9 @@ class completion_criteria_role extends completion_criteria {
 
    /**
     * Add appropriate form elements to the critieria form
-    * 
+    *
     * @param moodleform $mform Moodle forms object
-    * @param stdClass $data
+    * @param stdClass $data used to set default values of the form
     */
     public function config_form_display(&$mform, $data = null) {
 
@@ -75,9 +72,13 @@ class completion_criteria_role extends completion_criteria {
      * @param stdClass $data Form data
      */
     public function update_config(&$data) {
+
         if (!empty($data->criteria_role) && is_array($data->criteria_role)) {
+
             $this->course = $data->id;
+
             foreach (array_keys($data->criteria_role) as $role) {
+
                 $this->role = $role;
                 $this->id = NULL;
                 $this->insert();
@@ -98,13 +99,14 @@ class completion_criteria_role extends completion_criteria {
      * Review this criteria and decide if the user has completed
      *
      * @param completion_completion $completion The user's completion record
-     * @param boolean $mark Optionally set false to not save changes to database
-     * @param boolean $is_complete Set to false if the criteria has been completed just now.
-     * @return boolean
+     * @param bool $mark Optionally set false to not save changes to database
+     * @param bool $is_complete Set to false if the criteria has been completed just now.
+     * @return bool
      */
     public function review($completion, $mark = true, $is_complete = false)  {
         // If we are marking this as complete
-        if ($is_complete && $mark) {
+        if ($is_complete && $mark) 
+        {
             $completion->completedself = 1;
             $completion->mark_complete();
 
@@ -127,7 +129,7 @@ class completion_criteria_role extends completion_criteria {
 
     /**
      * Return a more detailed criteria title for display in reports
-     * 
+     *
      * @return string
      */
     public function get_title_detailed() {
@@ -160,4 +162,4 @@ class completion_criteria_role extends completion_criteria {
 
         return $details;
     }
-}
\ No newline at end of file
+}
diff --git a/lib/completion/completion_criteria_self.php b/lib/completion/completion_criteria_self.php
index 2dcfcaf0aee..065f00ff45b 100644
--- a/lib/completion/completion_criteria_self.php
+++ b/lib/completion/completion_criteria_self.php
@@ -37,10 +37,7 @@ defined('MOODLE_INTERNAL') || die();
  */
 class completion_criteria_self extends completion_criteria {
 
-    /**
-     * Criteria type constant [COMPLETION_CRITERIA_TYPE_SELF]
-     * @var int
-     */
+    /* @var int Criteria type constant [COMPLETION_CRITERIA_TYPE_SELF] */
     public $criteriatype = COMPLETION_CRITERIA_TYPE_SELF;
 
     /**
@@ -58,7 +55,7 @@ class completion_criteria_self extends completion_criteria {
      * Add appropriate form elements to the critieria form
      *
      * @param moodleform $mform  Moodle forms object
-     * @param stdClass $data
+     * @param stdClass $data Form data
      */
     public function config_form_display(&$mform, $data = null) {
         $mform->addElement('checkbox', 'criteria_self', get_string('enable'));
@@ -93,8 +90,9 @@ class completion_criteria_self extends completion_criteria {
      * Review this criteria and decide if the user has completed
      *
      * @param completion_completion $completion     The user's completion record
-     * @param boolean $mark Optionally set false to not save changes to database
-     * @return boolean
+     * @param bool $mark Optionally set false to not save changes to database
+     * @param bool $is_complete set true to mark activity complete.
+     * @return bool
      */
     public function review($completion, $mark = true, $is_complete = false) {
         // If we are marking this as complete
@@ -151,4 +149,4 @@ class completion_criteria_self extends completion_criteria {
 
         return $details;
     }
-}
\ No newline at end of file
+}
diff --git a/lib/completion/completion_criteria_unenrol.php b/lib/completion/completion_criteria_unenrol.php
index 5f9025ce911..62f30726d18 100644
--- a/lib/completion/completion_criteria_unenrol.php
+++ b/lib/completion/completion_criteria_unenrol.php
@@ -37,10 +37,7 @@ defined('MOODLE_INTERNAL') || die();
  */
 class completion_criteria_unenrol extends completion_criteria {
 
-    /**
-     * Criteria type constant [COMPLETION_CRITERIA_TYPE_UNENROL]
-     * @var int
-     */
+    /* @var int Criteria type constant [COMPLETION_CRITERIA_TYPE_UNENROL] */
     public $criteriatype = COMPLETION_CRITERIA_TYPE_UNENROL;
 
     /**
@@ -58,7 +55,7 @@ class completion_criteria_unenrol extends completion_criteria {
      * Add appropriate form elements to the critieria form
      *
      * @param moodleform $mform Moodle forms object
-     * @param stdClass $data
+     * @param stdClass $data Form data
      */
     public function config_form_display(&$mform, $data = null) {
         $mform->addElement('checkbox', 'criteria_unenrol', get_string('completiononunenrolment','completion'));
@@ -84,8 +81,8 @@ class completion_criteria_unenrol extends completion_criteria {
      * Review this criteria and decide if the user has completed
      *
      * @param completion_completion $completion The user's completion record
-     * @param boolean $mark Optionally set false to not save changes to database
-     * @return boolean
+     * @param bool $mark Optionally set false to not save changes to database
+     * @return bool
      */
     public function review($completion, $mark = true) {
         // Check enrolment
@@ -134,4 +131,4 @@ class completion_criteria_unenrol extends completion_criteria {
         $details['status'] = '';
         return $details;
     }
-}
\ No newline at end of file
+}
diff --git a/lib/completion/data_object.php b/lib/completion/data_object.php
index 4db32f5e05e..d0af3980393 100644
--- a/lib/completion/data_object.php
+++ b/lib/completion/data_object.php
@@ -37,16 +37,10 @@ defined('MOODLE_INTERNAL') || die();
  */
 abstract class data_object {
 
-    /**
-     * Table that the class maps to in the database
-     * @var string
-     */
+    /* @var string Table that the class maps to in the database */
     public $table;
 
-    /**
-     * Array of required table fields, must start with 'id'.
-     * @var array
-     */
+    /* @var array Array of required table fields, must start with 'id'. */
     public $required_fields = array('id');
 
     /**
@@ -56,10 +50,7 @@ abstract class data_object {
      */
     public $optional_fields = array();
 
-    /**
-     * The primary key
-     * @var int $id
-     */
+    /* @var int The primary key */
     public $id;
 
     /**
@@ -210,7 +201,7 @@ abstract class data_object {
     /**
      * Updates this object in the Database, based on its object variables. ID must be set.
      *
-     * @return boolean success
+     * @return bool success
      */
     public function update() {
         global $DB;
@@ -231,7 +222,7 @@ abstract class data_object {
     /**
      * Deletes this object from the database.
      *
-     * @return boolean success
+     * @return bool success
      */
     public function delete() {
         global $DB;
@@ -346,5 +337,5 @@ abstract class data_object {
      *
      * @param bool $deleted Set this to true if it has been deleted.
      */
-    function notify_changed($deleted) {}
+    public function notify_changed($deleted) {}
 }
\ No newline at end of file
diff --git a/lib/completionlib.php b/lib/completionlib.php
index e645d326926..c0a23c009e7 100644
--- a/lib/completionlib.php
+++ b/lib/completionlib.php
@@ -98,7 +98,7 @@ define('COMPLETION_UNKNOWN', -1);
 define('COMPLETION_GRADECHANGE', -2);
 
 /**
- * User must view this activit.
+ * User must view this activity.
  * Whether view is required to create an activity (course_modules/completionview)
  */
 define('COMPLETION_VIEW_REQUIRED', 1);
@@ -159,22 +159,13 @@ define('COMPLETION_AGGREGATION_ANY', 2);
  */
 class completion_info {
 
-    /**
-     * Course object passed during construction
-     * @var stdClass
-     */
+    /* @var stdClass Course object passed during construction */
     private $course;
 
-    /**
-     * Course id
-     * @var int
-     */
+    /* @var int Course id */
     public $course_id;
 
-    /**
-     * Completion criteria {@see completion_info::get_criteria()}
-     * @var array
-     */
+    /* @var array Completion criteria {@see completion_info::get_criteria()}  */
     private $criteria;
 
     /**
@@ -280,7 +271,7 @@ class completion_info {
      *
      * @param int $user_id User id
      * @param int $criteriatype Specific criteria type to return
-     * @return false|completion_criteria_completion
+     * @return bool|completion_criteria_completion returns false on fail
      */
     public function get_completion($user_id, $criteriatype) {
         $completions = $this->get_completions($user_id, $criteriatype);
@@ -537,7 +528,7 @@ class completion_info {
      * Calculates the completion state for an activity and user.
      *
      * Internal function. Not private, so we can unit-test it.
-     * 
+     *
      * @param stdClass|cm_info $cm Activity
      * @param int $userid ID of user
      * @param stdClass $current Previous completion information from database
@@ -1272,8 +1263,8 @@ class completion_info {
      *
      * Internal function. Not private, so we can unit-test it.
      *
-     * @param grade_item $item
-     * @param grade_grade $grade
+     * @param grade_item $item an instance of grade_item
+     * @param grade_grade $grade an instance of grade_grade
      * @return int Completion state e.g. COMPLETION_INCOMPLETE
      */
     public function internal_get_grade_state($item, $grade) {