How to Write a CER (Step-by-Step)

Have you been asked to write a CER for the first time? Although the process can seem complicated at first sight, CER statements are logical and follow a prescribed formula. Once you learn what steps you should follow, crafting a high-quality CER statement becomes surprisingly simple. Here’s how.

Basics: What Is a CER?

Good science aims to be objective, precise, and accurate. Scientists rely on the scientific, a time-tested method to ensure objectivity. The scientific process can be summarized in three key steps:

• Describe the problem precisely.
• Form a hypothesis that predicts a particular outcome.
• Observe, test, experiment, gather data. During this stage, scientists attempt to disprove, not prove, the hypothesis. Only the most rigorous science results from this method.
• As a next step, the data has to be clearly interpreted.
• Conclusions can now be made, based on gathered data.

A CER — short for “claim, evidence, reasoning” — statement is a framework used in science classes to  evaluate the scientific method or to engage in solid science. Students evaluate the three essential aspects of:

• Claim — what argument, claim, or hypothesis is being made?
• Evidence — what evidence is available to support the truth of the claim? Scientific sources should be cited to prove the accuracy of the claim.
• Reasoning — this portion of a CER statement evaluates why the presented evidence points to the truth of the claim, and employs logic and rhetoric.

The CER framework is not only used in science classes, but can also be put to work in the context of other subjects, such as English — where it may be used to analyze a literary work, for instance.

How to Write a CER Statement: Step-by-Step

Have you been asked to write a CER statement, or are you a teacher looking to use the CER framework in science or other lessons? The following guide can help you ensure that all steps are tackled correctly, and none of the key parts of the process are skipped.

1. Crafting the Claim

The claim must be a statement that can be debated, and that the students seeks to prove by means of the evidence provided in the next stage of the CER process. It should not generally be an indisputable fact, such as “gravity causes apples to fall to the ground”, as a CER statement seeks to generate debate and critical thinking.

In some cases, the claim will be provided for you. You will have the task of finding relevant evidence and crafting a logical conclusion that supports the claim. You do not have to personally agree with the claim to be able to do a good job as you follow the next steps.

2. Providing Evidence

This portion will require research. Students may generate evidence themselves, by engaging in experiments or gathering data through surveys, for instance. They may also, depending on the nature of the assignment, evaluate existing evidence.

If you are writing a CER for a scientific subject, this will typically involve gathering and reading reputable scientific sources, such as papers published in peer-reviewed journals, or indeed conducting your own experiments. In the context of science, students may look for the following aspects as they gather their evidence:

• Differences in results, between the test group and control group. As an example, let’s say that the differences in outcomes between biological pest control, in which organisms such as other insects are used to protect crops, and traditional pesticides, are being compared.
• Trends can be observed to come to conclusions as well. For instance, a student could analyze whether fast food sales go down when fast food prices rise, and whether this correlates with lower obesity rates. In this example, the relationship between obesity and fast food prices is examined.
• If the CER is written for another subject, such as English, the student would instead use the work being analyzed to look for supporting evidence. Statements made by the author, as well as researchers who have analyzed the work, can offer further insights into the meaning of the work.

3. Reasoning: Making Your Argument

Based on the evidence you used, examine why the claim must be true. Use logical reasoning and watch out for logic gaps that you may have missed — your reasoning should be water-tight.

4. Editing Your CER Statement

CER statements written for science subjects should consist of neutral, objective, language, and generally avoid first person statements. You are aiming to show why your claim is correct, using evidence and logic. This is why it is important to refrain from using language like “I believe”, or “I tested the popularity of 5 different types of peanut butter”. Opt for language such as “Tests were conducted” and “The data shows that…” instead.

The rules can differ slightly if you are writing a CER statement for a literary or humanities subject, which may be more argumentative and subjective in nature.

Examples of CER Statements

Before you can develop your CER statement, you will have to decide on the claim you are making. Examples of solid claims might include:

• Insect protein is an invaluable weapon in the fight against climate change. As you look for evidence to support this claim, you could cite data that illustrates the carbon footprint of cattle vs insect protein, as well as market research assessing the likelihood that people in countries where insect protein was recently introduced will accept this form of meat in large numbers. You could then demonstrate to what extent insect protein could reduce carbon emissions.
• Video games foster social skills in an increasingly isolated world. You would cite research on the positive social impact of multiplayer video games, as well as investigating the negative aspects. You could interview gamers and concerned parties. Write a conclusion based on your findings.
• Star Wars was the most influential film franchise of the 20^th Century. We list this example only because CER statements may be used outside of the sciences as well. You would likely examine box office sales and compare the number of pop culture references made about Star Wars to those made about other movies to support your conclusion.

6 Tips on Writing a CER Statement

As you brainstorm, keeping a few important tips in mind will help you craft a solid CER statement:

1. Choose a claim that you can defend, but that you could also reasonably argue against, especially in a literary context.
2. If, following your research, you find that the evidence in fact points to your claim being wrong, you will likely be able to amend it. You have learned something important, however, so your time was not wasted.
3. All the evidence you include in your CER statement should be relevant to the claim and the conclusion.
4. A CER statement is not a statement of opinion. Your CER statement should be based in evidence. Leave your views out of it. You do this by using words such as “this data demonstrates that…”, “this quote proves that the author’s intention was to…”, “from this, it follows that…”, and “this evidence points to…”.
5. Ensure that your conclusion must logically flow from the evidence you have presented. Explain why.
6. Use formal, academic, language throughout your CER statement.