Peer assessment: what is it and how does it work

Peer assessment is one of the most widely used formative assessment strategies in classrooms, yet it is also one of the most poorly implemented.

In the classroom, this type of assessment is often used to have students comment on and grade their peers’ work based on clear criteria. The process allows them to recognize what constitutes high-quality work and how to improve it.

In this article, we’ll explore what peer assessment is in detail, how it fits within the main types of assessment, and which examples work best.

With the following guidelines, you’ll have the information you need to decide when it makes sense to use peer assessment, how to design it, and what precautions you should take to protect your students.

What is peer assessment?

Peer assessment is an evaluation process in which students at a similar level evaluate their peers’ work using clear, objective, and previously agreed-upon quality criteria, with the goal of providing constructive feedback and promoting learning.

The goal of this assessment tool is not to assign a final grade, but rather to support the learning process by fostering skills such as self-regulation, frustration management, critical thinking, and respect for peers.

It typically involves comparing a piece of work (such as an essay, a presentation, or a solved problem) against an assessment rubric or checklist that the teacher has explained and modeled in class.

As a result, this active learning methodology enhances student motivation and engagement in the knowledge acquisition process.

Unlike traditional assessment, where the teacher is the sole source of judgment regarding students’ work, peer assessment turns students into active agents. Thus, they must analyze another person’s work and are required to apply the agreed-upon criteria, distinguish between stronger and weaker pieces of work, and—very importantly—justify their decisions.

Peer assessment in the U.S.

In the United States, peer assessment is viewed as a form of formative assessment, within what is known as “assessment for/as learning,” as outlined in the article by Yin et al. (2022) published in the National Library of Medicine.

Most institutional guidelines and best practices for incorporating peer feedback into assessment generally advise against using this method as the sole basis for high-stakes summative grading, such as final exams or certifications. However, it is often recommended for low-stakes assignments, drafts, and interim activities, where the goal is for students to receive more and better feedback.

What is the purpose of peer assessment?

We can summarize the objectives of peer assessment into four main points:

1. Supporting self-regulated learning: students evaluate others’ work using clear criteria. This forces them to understand what it means to “meet a criterion.” In addition, this experience carries over to their own approach to learning, helping them plan, monitor their progress, and decide what to improve and how.
2. Development of critical thinking skills: students learn to identify strengths and weaknesses, prioritize comments based on their relevance, and justify their judgments with evidence. These are skills with practical applications throughout their lives and in all areas.
3. Optimization of teaching time: initially, the teacher can use peer assessment as an initial form of feedback. This allows the teacher to focus their time on reviewing samples, moderating, and correcting common error patterns.
4. Reinforcement of content mastery: by analyzing how their peers approach the same task, students compare different approaches and consolidate their own understanding of the unit or topic being studied.

How does peer assessment work?

Peer assessment functions as a carefully designed teaching and assessment process that follows a structure involving goal setting, feedback training, scoring organization, and closing the supervision cycle.

Its central objective is to maximize the formative value of the experience, ensuring the reliability of the process and reducing the perception of unfairness among students.

Below, we detail these steps.

Define clear objectives and criteria

The first step in peer assessment is to define objectives, clarifying what is expected of students and translating these goals into observable criteria.

Using these criteria, the instructor designs an assessment rubric or checklist tailored to the group’s level. Before implementing it, the instructor must illustrate the modus operandi with examples so that students can distinguish between strong and weak assignments.

Train students to provide useful and assertive feedback

Next, the teacher should devote as much time as necessary to explicitly training students on how to provide effective and respectful feedback.

In this regard, students must understand that the goal is not to assign a grade, but to help their peers improve their assignments, exercises, and projects through specific, clear, and constructive feedback.

Organizing peer review and the use of scores

Once the criteria are clear and the students are prepared, the teacher focuses on organizing peer review.

In this regard, the teacher decides on aspects such as how many reviewers each assignment will have, how they will be assigned, whether the process will be anonymous, and what feedback formats will be used (oral, written, online, or a combination of all).

Likewise, the teacher must also specify how the scores will be used, that is, whether they will be for formative assessment only, whether they will count toward the final grade, or whether they will be combined with the teacher’s grade.

This information helps reduce misunderstandings and builds participants’ trust in the process.

Closing the cycle with review and reflection

In this final step, we enter the realm of metacognition, when students review the feedback they receive, they can use it to improve their own learning process.

The tutor’s role at this stage should focus on encouraging students to analyze which comments they found most useful and what specific changes they will make.

In this process, peer assessment ceases to be an isolated event and becomes part of a continuous cycle of improvement, where giving and receiving feedback becomes a regular and motivating part of formative assessment.

What is a peer assessment score?

A peer assessment score is the numerical or qualitative evaluation that a student assigns to a classmate’s work—at a similar stage of learning—based on the criteria that have been defined and explained in class.

Different methods can be used for scoring:

• Direct scoring: the student assigns an overall grade to the work using predefined levels or criteria. For example, from unsatisfactory to excellent.
• Criteria-based scoring: the classmate’s work is evaluated based on aspects such as structure, reasoning, presentation, accuracy, etc. The final grade is a combination of the partial scores.
• Average score among evaluators: several students evaluate the same assignment, and the average of the scores is calculated to reduce the impact of a single grade that may be biased.

The score is not used as a punishment; rather, it helps students understand how their work is evaluated and identify their strengths, areas for improvement, and the next steps to take to maximize their results.

Example of peer assessment in practice in higher education

In university courses that use cooperative learning methodologies, the introduction of a peer assessment system allows for the separation of the final grade from the evaluation of each team member’s individual performance.

To get the most out of the process, students evaluate their peers’ contributions based on standardized criteria for collaborative work, responsibility, and social skills. This approach is supported by institutions such as the Center for Teaching Innovation at Cornell University.

In the early rounds of peer evaluation, scores are not typically factored into the final grade. The goal is to help students develop their critical thinking skills and reduce interpersonal bias. In the final phase, however, the scores may be partially incorporated into the summative grade alongside the instructor’s assessment.

What is the result of this approach? A reduction in the instructor’s workload, especially when teaching large classes, greater student autonomy, and improved validity and reliability of group grades.

In what areas can peer assessment be applied?

Beyond the traditional university classroom, peer assessment can be applied in a wide variety of contexts, such as:

• Formal education: at any level, including elementary and secondary education, higher education, and vocational training.
• Digital and distance learning environments: in MOOCs and massive online courses, as well as in hybrid and blended learning.
• Professional and corporate contexts: in onboarding, training, code review, or scientific publishing (peer review).
• Creative and artistic spaces: such as creative writing, arts education, or design.

Beyond education and training ecosystems, peer assessment is extremely useful in other settings, such as marketing teams looking to improve proposals, for example.

What are the different types of peer assessment?

Peer assessment in the classroom can be classified based on aspects such as format, structure, anonymity, direction, or purpose. To give you a comprehensive overview of all these types, we’ve prepared the following table:

Advantages and Disadvantages of Peer Assessment

Peer assessment improves learning because it turns students into active evaluators: they internalize quality criteria, develop critical thinking skills, and receive immediate feedback from multiple perspectives, which allows them to strengthen their own mastery of the subject matter. However, it also faces significant challenges, particularly regarding the reliability of the process.

Peer assessment benefits: how it helps students learn

The following list outlines the main benefits of peer assessment for students:

• Students understand and reinforce success criteria: applying a rubric to a peer’s work forces students to reflect on what constitutes a good result. The process involves less emotional baggage than evaluating one’s own work and allows students to focus more objectively on the criteria before applying them to their own assignments.
• Develops critical thinking and analytical skills: the review process requires identifying strengths and weaknesses, filtering relevant information, and justifying each comment using predefined rubrics or criteria.
• Improves self-assessment and metacognition: when students observe how their peers approach the same task, they become better at identifying their own errors and discovering alternative strategies they hadn’t considered on their own. They also acquire skills to manage their own learning and accurately assess their individual progress.
• Acquires and develops social and communication skills: students learn to communicate assertively and professionally, participate in conversations where they formulate hypotheses, and foster deep reasoning and social-emotional learning.
• They receive immediate feedback: comments and analyses from classmates help students broaden their perspectives and expand their available techniques. All of this becomes a set of tools that helps them proactively self-correct, thereby improving their own learning process.

In addition to the student benefits just discussed, peer evaluation is also beneficial for teachers, as it provides a deeper understanding of different learning styles, the class’s difficulties and roadblocks, and the strategies that yield the best results.

Disadvantages and limitations of peer assessment

Peer assessment also presents significant challenges that you need to be aware of in order to avoid them when implementing it:

• Lack of technical competence: the reliability of feedback depends on the evaluator’s level of mastery of the subject matter. When the student does not fully understand the material, they may provide inaccurate or counterproductive feedback.
• Interpersonal biases: one of the teacher’s challenges is to prevent the objectivity of grades from being distorted by personal affinities or rivalries.
• Student resistance: at times, the teacher must find a way to overcome the fact that some students do not recognize the pedagogical authority of their peers.
• High administrative burden: the success of peer assessment requires upfront effort. If the process lacks clear grading rubrics, training in assessment, and constant faculty supervision to adjust guidelines based on the evolution of the practice, the exercise will lose its rigor and usefulness.

Is peer assessment reliable enough for grading?

Peer assessment is highly reliable as a learning tool, but much less

consistent as a grading instrument. This explains why most U.S.

institutions use peer assessments as one of the criteria to consider,

although they typically carry little weight in the final grade.

Available research supports this caution. A meta-analysis published in Educational Psychology Review (Double, McGrane, & Hopfenbeck, 2020) confirmed that peer assessment improves academic performance, but its accuracy as a grading measure depends largely on its design.

In fact, one of the biggest obstacles is often the lack of reliability in the process. To improve it, you can apply these techniques we’ve compiled from institutional guides—such as the one from Cornell University’s Center for Teaching Innovation—on the subject:

• Include multiple evaluators per assignment so that the average of the scores mitigates individual biases.
• Incorporate calibration sessions in which students practice scoring sample assignments before evaluating their peers.
• Use analytical rubrics that break down quality into observable criteria.
• Include moderation by the instructor, who should review outliers and adjust grades when raters disagree significantly.

With these best practices, peer grades can complement the instructor’s assessment. If these precautions are not taken, peer assessment remains formative rather than summative.

When assessment is conducted remotely or via digital tools, integrity, objectivity, and supervision can become more complicated. In this context, the use of appropriate tools becomes essential.

To address the challenges of remote supervision without overburdening instructors, proctoring technology is the ideal tool.

In this regard, institutions and training centers should select solutions that meet their needs, evaluating criteria such as the type of feedback, the level of supervision, and the ease of native integration with the platforms and Learning Management System (LMS) they use.

Based on these criteria, SMOWL’s proctoring plans offer flexible and innovative models that adapt to each exam or type of remote assessment, creating secure, respectful, and streamlined environments. You can see for yourself by requesting a free demo.

Going further

If you’d like to delve deeper into peer assessment methodologies and discover how to successfully implement them in the classroom, you can continue exploring these resources:

• Poorvu Center for Teaching and Learning, Peer Review Groups & Writing Feedback: an article from Yale University that details how to structure blind or anonymous group review processes to avoid interpersonal bias.
• Center for Teaching & Learning, Student Self-Assessment: a detailed analysis from the University of Colorado Boulder on how to link peer assessment with self-assessment to foster critical thinking and student autonomy.
• Stanford Teaching Commons, Peer review: a practical guide focused on how to train students before the assessment to maximize the rigor and reliability of grades.