Forming Evidence-based Conclusions and Debriefing CER in Science K-8

With KnowAtom’s Next Generation Science Standards (NGSS)-based curriculum, these student-led science investigations involve formulating a plan, using materials for a specific purpose, and making conclusions about what the experiment shows. Students work together to decide whether the plan they create solved the problem identified by the class, and whether their team’s hypothesis answered the class’s question. Students gather evidence and use it while investigating the phenomena, with help from the scientific or engineering design process.

The final step of this process is forming conclusions and conducting a debrief with the class. The following chapters will help you communicate to students what makes a conclusion complete. It will help you prepare and implement debriefs in the classroom, and provide ways to engage students to share their own conclusions. In the KnowAtom lesson routine, making conclusions is a two-part process that includes 1) creating a conclusion, and 2) sharing, discussing, and learning from the different conclusions that students create.

There are tools that teachers can use during the lesson debrief to help students make strong conclusions from the evidence they’ve collected. With hands-on investigations led by student groups, some of the best learning occurs when things go wrong. Making conclusions from experiments that didn’t go as planned, comparing evidence between student groups, and sharing conclusions with the entire class is an important way for students to learn from their mistakes and make high-level connections between the subject matter and the world around them.

What is a CER Conclusion?

A CER Conclusion is a model that students can use to report the results of their hands-on scientific inquiry. Once they have collected and analyzed their data, the students need to choose what to report as their conclusion, and how to do it clearly and effectively. The CER Conclusion model gives students a simple tool to deliver their results to the class just like a scientist or an engineer would. Forming a CER Conclusion brings scientific process and engineering design process to a close by using the investigative phenomena gathered to reflect back on the hypothesis or prototype tested.

• Applying the CER model to a science classroom, an explanation consists of:
• Framing the conclusion with the problem or question
• Identifying the proposed solution or hypothetical answer being tested
• A claim about that solution or answer’s validity
• Evidence from students' data to support the claim about validity
• Reasoning and reflection that extends a scientific principle to describe why the evidence supports the claim

What Makes a Complete Conclusion

Consider these frequently asked questions from KnowAtom teachers around the country:

• The students know that they were right, or that their hypothesis was true. Is that enough?
• What should I look for in a conclusion so that I know that it's complete?

The answer to the first question above is no. It's not enough! To engage students in high-level thinking, they should be articulating why their hypothesis was true or false. They should be connecting that hypothesis back to the question posed at the beginning of the lesson. Students who work out on their own what conclusions to make from the evidence they collect will be better prepared to respond to new questions and situations both in the classroom and outside of it. Understanding how to engage in the scientific or engineering design process – and strengthening their own critical thinking skills – is key to their long-term success.

One common response from teachers when thinking about the scientific and engineering design processes is: Wow, that's a lot of writing. How do you get kids to work so hard?

Engaging in critical thinking does take a bit of grit. For students to make their own conclusions – whether they are writing those down or sharing them verbally in class – takes a lot of thinking. It can also be discouraging, especially at first, because a student’s first thoughts and conclusion might not be complete, and more work may be needed to support and clarify it.

 

For students who think ‘Well, I know it’s right, shouldn’t I get credit for that,’ my response is – if you haven't communicated a complete conclusion, then you haven't communicated to me yet that you should receive credit. Instead, let’s work on how we communicate a complete conclusion. Students at all grade levels can use the scientific process and come up with basic conclusions. For younger students, scaffolds are available to help, including tools like a conclusion helper.

First, consider the scientific process. When you think about students being released with responsibility over that process, they are working together to complete each part – from designing a lab to choosing materials and collecting data. Teachers can implement checkpoints throughout that process to help keep the students on track. Once students have executed the lab plan that they designed, collected their data, and returned their materials, they are ready to use the data to form a conclusion.

Using a checkpoint between creating conclusions and the lesson debrief is important. Without it, students may come to the debrief with something that is not really a conclusion. Instead, they may present more of a statement than a conclusion, leaving the class to try to figure out exactly what they mean. To use checkpoints to help students build strong conclusions before the debrief, teach them to focus on communicating these five key parts of a complete evidence-based conclusion.

Five Key Parts to Evidence Based Conclusions in Science

While most teachers have heard of the CER model of writing and used it in an ELA context, we’re going to focus on how to use it appropriately in the context of K-8 science and engineering. The five key parts to creating a complete evidence-based conclusion are:

• 1. Question
• 2. Hypothesis
• 3. Claim
• 4. Evidence
• 5. Reasoning

Using this step-by-step guide, teachers can help students make connections between what they have done with scientific or engineering process in class and why they are doing it. Using this model for scientific conclusions, students must articulate clearly what they have accomplished by making a claim, gathering evidence, and making conclusions. By engaging the students to ask (and answer) WHY – why do they think that happened, why did they make that conclusion – we can help them link these five key parts together, which just happens to be the formula for a complete conclusion.

What we usually think about when we think of the claim, evidence, reasoning (CER) model is just that – a claim, followed by evidence, connected by reasoning. But it's important to recognize that we're making a claim about something. In science, we're making that claim about a hypothesis. So that begs the question – why do we have a hypothesis? Well, it's because we're trying to answer a question.

When a student forms a conclusion, they should do it while thinking about (and restating) the question they were asked to answer. Students should then consider what they thought the answer to that question might be, which is their hypothesis. After students collect evidence, they must make a claim about whether their chosen hypothesis is true, false, or inconclusive. Then, the students must provide supporting evidence for that claim.

The last step is an important one. Reasoning is explaining how the evidence supports the claim and what that claim means about their original hypothesis. The reasoning is like connective tissue, it holds all 5 parts of the conclusion together. This process should be by students to draft their conclusions before students begin their classroom debrief at the end of the lesson. They should come prepared to listen and share conclusions aware of these five-parts of a CER conclusion in science.

Using Open-Ended Questions to Encourage Critical Thinking

Whether I am in a first-grade classroom or an eighth grade one, my first question for students I talk to as I go around the class during an experiment is the same – WHY? For example, ‘Why are you working with owl pellets?’ With this question, I am seeking whether students are really connecting what’s happening in their experiment with the original question we decided on as a class. If they are, the students will share with me what that question is, and that they’re trying to figure out if their hypothesis is true or false. If the students say something like, “We think that owls eat rats,” I can ask, “Why do you think that? Why are you trying to find out whether owls eat rats?” That exchange will help lead us back to the question which frames everything from the anchor phenomena to conclusion.

A conclusion is not only about its five parts. It's also about how students are linking the parts together. What’s important is the quality of those links. In the example above, when talking to second graders about owl pellets, I can identify their skill level and their level of concept mastery just by asking them some simple questions, seeing what they bring up, and identifying how ready they are to link the parts together and how strong those linkages are.

Beginning around 4th grade we’re looking at whether students are linking the five parts together in writing a complete conclusion.

A good model is:

In this experiment we were trying to answer (question), so we tested (hypothesis) as a possible answer. In our experiment, we found that this hypothesis was (true/false) because (evidence).

In this example, you can see that each of the five parts exists and that in forming the conclusion, each of the parts are linked. One way to discover these linkages is to think in reverse.

Whether students are sharing verbally or in writing, the teacher should be able to see that each part links back to the one before it. When the students are drafting their conclusions, a checkpoint can provide a way for the teacher to help the students refine their conclusions, ensure it includes each one of the five key parts, and edit it down to be as clear and concise as possible. This clarity will help make the linkages even stronger. Through this back and forth with students as they talk through their conclusions, the teacher should push back with questions like:

• Why did you have that hypothesis?
• How do you know that claim is true?
• How do you know that the hypothesis is false?

Questions like these help students pull together the missing pieces for themselves and develop deep scientific communications and writing skills. As use your teacher curiosity, listening skills, and open-ended questions to push students to a deeper level of knowledge. Reflect on what students are telling you: Are they missing evidence? How do you know the hypothesis is true? Students must prove their claim and include that supporting information in their conclusion. One of the pitfalls of students taking the lead in the scientific process is that when they’re finished collecting evidence, they think they are done. But we’re not done, and the final step is one of the most important.

By engaging students with open-ended questions, and implementing checkpoints, we can get them to think about making strong conclusions about the evidence they’ve collected. The five-step model for CER in science is something you can share with your students in advance and use in every experiment, to help them understand exactly what you’re looking for in a strong conclusion.

How to Write a CER Conclusion

A student’s CER Conclusion provides a clear and concise explanation of the results of the scientific process or engineering design process.. First, it starts with the problem or question the student team identified. Then it states the solution or answer the student was investigating as a solution. This is an important and often overlooked part of a CER conclusion for science and engineering which frames the claim, evidence, and reasoning.

Next, the students should include a claim about the effectiveness of the solution or answer they tested followed by specific data and observations that support their claim. This evidence should be the result of analyzing the investigative phenomena collected from their hands-on investigation.  This is where they showcase their data collection and analysis skills.

Finally, the students must explain clearly by extending their reasoning to how their evidence supports the claim they made. They must explain the reasoning that backs up this conclusion. Students should not be graded on whether the solution or answer they tested was true or false but rather they should be graded on their understanding of the outcome of their experiment and their ability to reason and explain it with the data they gathered.

How You Set Up Debriefing and Sharing Conclusions Matters

During the classroom debrief, there will be differences in the claims that students share. That’s because the student groups made different hypothesis in the beginning. Differences also happens when students make mistakes during the data collection process, or during their analysis. During the debrief, the class should work together to identify those differences and uncover why they occurred. In some cases, these differences will make a profound impact on conclusions and in other cases differences won’t matter at all.

One way to do this is through the Four Corners classroom activity. To start, break the students up by similar hypotheses, and ask them to chew on their differences as a group. This activity gets students to compare and contrast their data, lab planning, and analysis. As a group, each “corner” can then share the evidence they have decided on that shows that their hypothesis is true. The rest of the class should be charged with listening for the five key parts, and whether the team has provided enough evidence to connect and support their claim. Then, classmates can share their feedback.

To probe for student feedback, you can ask open-ended questions like:

• How convincing of a conclusion do you think this is?
• Are there any weak points?
• Are there any points that are really strong?

The students might share feedback that shows the evidence is unclearly linked to the hypothesis, or that the evidence their own group found is entirely different – so one of the ‘corners’ must have made a mistake in their measurements. As the students discuss these differences, they are thinking more deeply about the entire process. They are developing critical thinking skills as a habit, a new way of thinking deeply about a problem and developing their own conclusions. In that way, the conclusions students create in the future will get exponentially better each time.

To prod the student groups to share their conclusion more clearly, you can use open-ended questions like:

• What is it that's true? In your data you're saying it, but I don't know what it is.
• What do you mean by true? Why do you think that hypothesis is true?

What a student-led debrief like this does is create opportunities for students to implement thinking moves. Instead of the teacher doing the figuring out – the students are making those thinking moves. They are developing important career skills and the only way they can refine them is if we push back and challenge them with open-ended questions.

One way to do this is to focus more on the questions below on the right, and less on the left.