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

Key Learning Objectives:

  • What is a CER Conclusion
  • What Makes a Complete Conclusion
  • How to Write a CER Conclusion
  • How You Set Up Debriefing and Sharing Conclusions Matters
  • Tools: Motivation and Using Checkpoints and Concept Maps to Debrief Thinking

The focus of this article is on forming claim-evidence-reasoning (CER) conclusions and debriefing in NGSS Science - the fifth and last step in the KnowAtom lesson routine, and an important way to finish each lesson. When using the KnowAtom lesson routine, students discover phenomena, discuss it, and then try to answer a question or solve a problem related to it. With hands-on science instruction, students have the opportunity to be scientists and engineers, while they respond to real world problems and work together to solve them.

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.

Engineering Process
Scientific Process

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.

Thinking Moves

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

Less focus on:

  • What did you learn?
  • What did you notice?
  • Did anyone learn something new?
  • What do we know now?

More focus on:

  • What makes you say that?
  • How is that different than ____?
  • These claims are the opposite of each other. Could they both be true?
  • How does that evidence support your claim?
  • What would you want to test to know for sure?

The questions on the left can be used earlier on in the lesson, during the Socratic dialogue or after the reading portion, as conversation starters. At that time, we’re beginning at the surface and then drilling down. But when the class is at the conclusion part of the lesson, these questions are too surface level. At this point in the lesson the teacher needs to be pushing the student groups harder, asking them to consider their evidence and conclusions, and defend them. If there are different conclusions – that’s okay! That’s one of the best reasons not to model the process first for students. When students take the lead, we’re going to see some creative problem solving going on in the classroom. And we’re going to see some different opinions and conclusions to compare in the debrief.

Students ultimately want to know if their hypothesis is correct – and that’s going to drive them to figure it out and contribute to the group. Students are going to make mistakes in their lab planning, their evidence gathering, and in writing their conclusions. Identifying those mistakes on their own when comparing their results and conclusions to their peers is an important lesson, as is the realization that making mistakes in science is okay.

Similar to Socratic dialogue, when students are pressed with open-ended questions during checkpoints and the debrief, they start to ask each other those type of questions when they are working in teams. The students begin to ask more questions like these themselves during debriefs. The teacher’s role as facilitator starts to change to more of an observer than the one asking all the questions, as the students take the lead during the debrief.

It’s natural when you start the process for older students to clam up when you ask them questions like these. “It’s so hard, I don’t know,” they’ll say! One way to help is by showing your own curiosity about the process the students took and the conclusions they made. “I am really curious, what makes you say that?” Those sorts of prompts can help take the sting out of open-ended questions that can feel personal to students.

Another way to encourage this type of student growth is by rewarding it when you are grading. Don’t grade students based on their conclusions – and whether something is true or false. Instead, grade the student groups based on their growth and on their classroom engagement, their engagement in thinking. If a student identifies their learnings or mistakes and articulates how they would do something different in the future, that shows a high level of engagement and growth. It also means they are thinking ahead too, which is something we want to push students to do.

Tools: Motivation and Using Checkpoints and Concept Maps to Debrief Thinking

One of the things that teachers often ask is, ‘How do you motivate kids to do this?’ Especially when you’re feeling pressed for time with a lot of material to cover, you may be thinking – wouldn’t it be quicker and easier to just give them a model and ask them to do it? The problem with this instructional model is that it actually demotivates students. It also separates students from the meaning of each of the five parts that make up the conclusion and actually makes it harder for them to connect those concepts into something cohesive and see the overall value of the experiment.

In the first experiment, researchers paid people to write letters on paper. Each time they turned in a sheet of paper they could allowed them to continue working but they reduced the amount of money paid for the next sheet they turned in. The research shows how different motivations impact results. Think about how this might be applicable to the classroom. The good news is that adding motivation doesn't seem to be so difficult. The bad news is that eliminating motivation seem to be incredibly easy.

One analogy to school is whether you provide feedback to students on their work and how. When you think about the interaction between the experimenter and the participants in this video, think about that as a checkpoint. When students come to a checkpoint to tell you what they've done, and you listen to them and ask questions, that's not just acknowledging them. The interaction is much deeper than that and it drives students to work harder.

When we give students the opportunity to write their own lab procedures, they are investing in the steps of what they're going to do. If we just hand them the procedure, then it's almost too easy – it’s not their procedure it’s your procedure. Instead, by giving them the opportunity to create something that's theirs, now they really want to find out what happens. If we over scaffold things for kids, some might get an A. But what kind of confidence do they really get from that accomplishment? Do they really believe that's an A that they earned? The greater the cognitive demand that is on the student and the more personal investment the more they're willing to engage with it, and the greater their sense of satisfaction once they've achieved the goal.

Science should be messy. If students have to do a few U-turns, have to cross some things out, have to try again – that causes them to love it even more. Instead of looking at that messiness like we’re not doing a good job as teachers, we need to look at the investment the students are making and the growth they are experiencing when we give them the space to create. We need to reevaluate what we value – and if its students investing in the work – then it doesn’t matter if the final product is perfect. What matters is how we got there, together.

The more you involve students in the process of evaluation and in thinking about what other people are doing as well as what they are doing, they're gaining an understanding that what they have done is not necessarily the only or best way to do it. There might be other ways. They're learning a really important skill – to listen to and evaluate other perspectives.

One big takeaway is that we’re building students’ agency. As they learn that they have the ability to shape not only experiments and to answer questions and solve problems, but they are also learning how to shape the world around them using these skills and their thinking. That’s a deep life skill and something they’ll use to overcome challenges throughout their life.

For more tools for debriefing, visit our NGSS Resources for Teachers page.

Four Corners – Implement this in your debrief routine, similar to the description above but you can put your own spin on it too.

Generate-Sort-Connect – This popular routine can help all students use their agency, evaluate options, and make choices at each stage of planning. First, student pairs generate ideas. As a group or the whole class, students sort those ideas into groups, with the help of the teacher. The students then connect those sorted groups to their plan. During Sort and Connect, teachers should ask questions that get students to elaborate and clarify, which helps other students to better understand and consider what is being shared.

Concept Maps – These can be used to help, especially at the end of the debrief to get students thinking about what their conclusions mean in terms of the connections they can make to past lessons and current knowledge.

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