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Peer Grading in Online Classes: Does it Work?
Posted on July 6, 2012 by onlinelearninginsights
http://onlinelearninginsights.wordpress.com/2012/07/06/peer-grading-in-online-classes-does-it-work/

Is student grading good enough to use? A loaded question – and though it is context-dependent, the answer is yes. Yesterday I peer-graded six student midterm exams in the Introduction to Sociology course I’m taking through Coursera, along with 30,000 other enrolled students. In this learning environment, also known as a MOOC, peer grading is the only option, though it did motivate me to research its effectiveness and applicability to online courses for credit (the context for this post). Intrigued, I could see the potential in light of the online program at my workplace, not only from a time-saving standpoint for the instructor, but also for the potential in enhancing the student learning experience.

Enhanced Learning
I see the value of peer grading for what the student gets out of it, more than for the time it saves the instructor. I experienced this value first hand as mentioned above. The exam in question consisted of two short answer questions each requiring 250 words, and an essay response requiring 750 words. Though tedious [90 minutes of my undivided attention], I was far more familiar with the course concepts after the exercise, it was well worth the time.
Several of my classmates reported the same phenomenon via the discussion board – the deeper learning experienced while grading their peers. Below are snippets from select posts on the discussion board from the Coursera Introduction to Sociology course:

“…I actually enjoyed the peer review part mostly because of looking at different answers, giving me more perspective from an group of people all from different cultures. Not only that, but I felt I was able to be unbiased while grading my own work ….” Greg

“I’ve learned a lot through the peer assessment, and even though maybe the scores will not be perfect, everybody who goes through that process will have now a better and more complete understanding of the first half of the course.” Horacio

“For what it’s worth, one of the essays I corrected didn’t seem too good on first reading but when I checked it against the rubric, lo and behold, most of what was required was there.” Ron

“In my experience as an educator for over 25 years, it’s often the case that we think our grades should be higher than they are. ….the rubric was great, very thorough and complete…” Kendall

Accuracy
How accurate is peer grading? Another interesting question, and it depends upon the perspective. The viewpoint that most educators are familiar with, is where the instructor’s grade is the benchmark – his or her grading is the standard for measuring accuracy.
This is the method used in a research study by two biology professors at the University of Washington which determined that on a per-question basis, students were more generous in grading, actually 25% more, “0.27 points—roughly a quarter point on each 2-point question”. However, despite the differing grades, authors support peer grading and suggest further research be done to examine its value and the role peer grading can play in enhancing student learning. (Freeman & Parks, 2012).
Mechanics
How can student grading be effective within an online environment? Effectiveness depends upon the thoroughness and specificity of the rubric. A grading tool that guides the student through assessment of short answer and essay questions is critical. Below is an example from the research study mentioned earlier [a biology course was used for the study]. There may be five or six of these questions for each point within a given question.

Sample answer: If the two species mate on different fruits,
then no gene flow occurs and they are reproductively isolated.

Rubric

• Full credit (2 pts.): Clear articulation of logic that mating on different fruits reduces or eliminates gene flow—a Prerequisite for speciation to occur.
• Partial credit (1 pt.): Missing or muddy logic with respect to connection between location of mating and gene flow, or no explanation of why reductions in gene flow are Important.
• No credit (0 pts.): both components required for full credit missing; no answer; or answer is unintelligible. (Freeman & Parks, 2012)

Recommendations
To begin peer grading in an online course consider the following:

• Create your own rubric that provides standards for each point the question is worth. For instance if a given questions is worth 6 points, 6 statements will need to be developed, similar to the one above.
• Create detailed instructions for students that clearly outline how peer grading will work.
• Set-up the process so that students grade a minimum of 3 peers’ assignments/exams and self-grade his or her own.
• Average the peer scores and include the student’s self-graded assignment.

Though creating a peer review exercise is time consuming at the outset, rewards are tremendous. First, for the potential time saved by the course instructor in grading, and second, [perhaps the most important] is the value that peer grading provides for the student.
References:
Freeman, S. & Parks, C. How accurate is peer grading (2010). CBE—Life Sciences Education. Vol. 9, 482–488.
Resources:
Peer Review, Peer Grading, JaZahn
UCLA’s Calibrated Peer Review, Eric Mazur. This is a software program/platform that can handle and support peer grading for large classes and/or institutions that plan to implement peer grading in several classes.