## 1 Introduction
### Peer Assessment
#### 1.2.2 Peer Assessment in Moodle  
Table 1 purposely omitted Moodle. Moodle is an open-source learning management system, written in PHP (PHP: Hypertext Processor), which supports the creation of online learning communities in different teaching and learning delivery modes (blended learning, online learning, flipped classroom, etc.). Moodle is the most used learning platform in the world, with 20 million registered courses, 175 million users and 109,000 sites in 234 countries [53]. Moodle has a student-centered design, facilitating collaborative learning and interactions between students and instructors, as well as among students in the virtual classroom. Three activity modules have peer assessment functionalities in Moodle: workshops, message boards, and the database module, each with its own advantages and disadvantages [54]; of the three, Moodle Workshops are the most used for self- and peer assessment, as they have by and large the largest set of functionalities to support peer assessment activities. In Moodle Workshops, students complete and submit their assignments following a series of five phases planned by the instructor which include: setup, submission, assessment, grade calculation, and closing of the activity. The progress of the activity is visible in the Workshop Planner Tool, along with all the tasks the user needs to perform during that phase and the duration of the phase. The peer assessment process is based on the idea that students submit their own assignments and then receive a predefined number of submissions from other students that they must review and assess, anonymously or not, according to the instructions and assessment criteria set by the instructor; if the instructor requests self-assessment, students must assess their own submissions too. During the setup phase, instructors can modify all the following workshop settings: dates, grading strategy, information, assessment rubrics, etc. Students cannot perform any activity while in the setup phase. In the submission phase, students are allowed to submit their assignment. The instructor can define the start and end dates of submission, as well as check the current status of submission of all students. The assessment phase is when students perform and submit their assessment of other students' submissions (and of their own submission, if self-assessment is enabled) until the specified end date and time. Depending on the setting, students must submit a final grade or grade different aspects of the assignment based on an assessment rubric; students can also provide specific feedback about the different aspects of the rubric, as well as a global feedback about the submission. Assessment is followed by grading, which involves calculation of the final grade and provision of feedback for students, both authors and reviewers. The submissions cannot be modified during this phase. Instructors can also add their own grading and publish the results. Moodle uses a grading method called \"comparison with the best assessment\", which tries to imagine what a hypothetical absolutely fair assessment would look like and measures the \"distance\" from other assessments to this best assessment, with the following five options associated with how strict the comparison should be: very lax, lax, fair, strict, and very strict. In this stage, instructors can also grade reviewers and provide feedback about the assessment. Closing means that the grades are written to Moodle's Gradebook and made visible to students. Students can then view their submissions and the reviews and feedback received, opening a space for self-reflection. An interesting feature of Moodle Workshop is that, in addition to the submission grade (the one given by one student to another), Moodle also calculates an assessment score, which indicates how close the grade given by a student is to the average grade of the assessed student. This gives an idea about how \"good\" or reliable a student is at assessing the work of their peers; Moodle allows different ways to calculate assessment scores.