Guest Blog by GLOBE Teacher Ellen O'Donnell: Writing Conclusions using CER Framework

Please welcome Guest Blogger Ellen O'Donnell, a GLOBE teacher from Deerfield Community School in Deerfield, New Hampshire.

This is the next blog in a series of posts by GLOBE teachers sharing classroom experiences to support the student research process. The series is supported by NSF funding for the United States Regional Student Research Symposia. If you are a teacher interested in contributing, please contact Haley Wicklein for more information.

Thank you to Ellen for sharing! This is a picture of Ellen's students attending the Northeast & Mid-Atlantic Regional event last year hosted by NASA Goddard.

Last year I watched several webinars which were developed for teachers whose students were participating in the GLOBE science fair. While they were all good, one really stood out to me and basically changed the way I taught, "Writing Conclusions using the C-E-R Framework."

It has been difficult getting students to effectively use evidence to justify their conclusion. This webinar introduced the concept of CER, the claim, evidence and reasoning framework for talking and writing, which has been developed by Kate McNeill.

This framework made so much sense to me that I immediately ordered her book, “Supporting Grade 5-8 Students in Constructing Explanations in Science,” McNeill & Krajcik, and quickly read it. McNeill, Zembel-Saul & Hershberger wrote a book for younger students, “What’s your evidence?” which is also great. Each book comes with videos of teachers using this method and I created my own lesson plan after watching some of these videos.

My students had recently done independent investigations on the human body and their conclusions were lacking in clear statements about what they had found, as well as using the data they collected to support their conclusion. I started off my class saying that I was the best gardener in New Hampshire. I then went on to say that I was the best gardener because I have a very large garden, I love to garden and I grow many different types of flowers and vegetables. The students soon realized that my evidence really didn’t support my claim which led to a great discussion on what is good evidence and how one needs to use evidence that supports your claim (reasoning).

We then went over some of the conclusions that they had submitted to me. I think that it is very effective to actually use some of the students own work, albeit anonymously. I projected their conclusions on the board and then called on a volunteer to come up and circle the claim.

A claim is a simple statement answering your original question and is easy to create, but you would be surprised at how many of my students never included one in their conclusion.

We then underlined the evidence, discussed if the evidence supported their claim, and afterwards highlighted the reasoning.

The reasoning is probably the most difficult for students, but with practice they get the concept. I love the reasoning part because it supports what students already know and validates their knowledge. For instance, I recently gave students a chart with 7 different liquids and they had to determine which liquid is water based on physical properties. One of the columns looks at clarity and another as to whether salt dissolves in water.

Students already know that water is clear, they see it all the time. They also know that salt dissolves in water as all my students have been to the ocean.

It is very important that we get students to connect to the life experiences they have already had and use this knowledge in their reasoning.

The last part of the CER framework for older students is the rebuttal. I call this the counterclaim with my students as this is the term they use in their language arts classes when they write persuasive essays. The rebuttal explains why your claim couldn’t be something else. In my water example, it is why it wouldn’t be the other substances.

I have started slow with the rebuttal and did not require it at first. I wanted my students to focus on the first three parts; claim, evidence and reasoning. However, several of my more advanced students took the challenge and included rebuttals in their conclusions. This allowed me to share their work with the class and now most of my students include rebuttals.

This practice was instrumental in getting students to  identify the parts of the conclusion and to see if one or all of these parts were lacking. After the lesson I asked the students to rewrite their conclusions based on our lesson. I also gave them the visual of the framework from Kate McNeill’s book:


Used with author permission. McNeill, K. L. & Krajcik, J. (2012).
Supporting grade 5-8 students in constructing explanations in science:
The claim, evidence and reasoning framework for
talk and writing. New York, NY: Pearson Allyn & Bacon.



I was very impressed with the rewrites that I received from students. While several conclusions still needed work, they had gained a great deal of progress on the rewrites.






Since then I have implemented peer review in my classroom when we write conclusions. I have found it to be beneficial for students to critique each other's work. I created this sheet for my students to use.

In conclusion, if you want students to write good scientific conclusions, use the CER framework. In addition, look for any opportunity you can for students to practice writing conclusions. I even slip them into assessments!


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