function dozent_get_instructor_rating( $user = null ) {
		global $wpdb;

		$user = dozent_get_the_user( $user );

		$ratings = array(
			'rating_count' => 0,
			'rating_sum'   => 0,
			'rating_avg'   => 0.00,
		);

		if ( empty( $user ) ) {
			return (object) $ratings;
		}

		$instructor_id = $user->ID;

		$rating = $wpdb->get_row( "SELECT COUNT(reviews.rating) as rating_count, SUM(reviews.rating) as rating_sum  
		FROM {$wpdb->dozent_instructor_courses} courses
		INNER JOIN {$wpdb->dozent_reviews} reviews ON courses.course_id = reviews.course_id
		WHERE courses.instructor_id = {$instructor_id} ;" );

		if ( $rating->rating_count ) {
			$avg_rating = number_format( ( $rating->rating_sum / $rating->rating_count ), 2 );

			$ratings = array(
				'rating_count' => $rating->rating_count,
				'rating_sum'   => $rating->rating_sum,
				'rating_avg'   => $avg_rating,
			);
		}

		return (object) $ratings;
	}