Convincing Arguments Come from Evidence and Reasoning

A convincing argument for a new idea backed up with strong data is the driver of growth and change in accepted disciplinary knowledge. A fundamental part of how the scientific enterprise works is having scientific arguments, based on solid evidence and reasoning, pass through the peer-review process.

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What is Evidence?

It can be tricky for students to see the difference between data and evidence. Afterall, data can serve as evidence. And it is common to hear the words used synonymously in everyday conversations. All qualitative and quantitative records collected during an investigation are the data. From this total information, the subset that is used to support or refute a claim is the evidence.

Subtleties of relevant, reliable, and valid data may not be obvious to students. Data should be excluded as evidence if:

• The data are not relevant to answer the research question.
• Measurements were recorded with errors.
• Observations were clearly biased.
• Other factors call into question the accuracy or quality of the data.

Students may not also see that existing data, not collected by them during the course of their investigation, can be secondary sources of evidence.

The Claim – Evidence – Reasoning Scaffold

A Claim, Evidence, and Reasoning chart is a commonly used template, particularly in middle schools, to help students think about what the evidence means. These charts have a place for students to also fill in their questions, so they can easily visually check to see that the data address the research question. The side-by-side columns of Claim and Evidence help students frame a particular claim based on a particular piece of evidence and make discordance between these more evident.

Regardless of whether you use such a template, encourage your students to make explicit connections between their concluding statements and the supporting evidence. In justifying why their data count as evidence to support their claim, students reveal their scientific reasoning skills.

Prompts can help students consider not only the internal consistency of their research findings but also their generalizability.

• How would you interpret the evidence?
• Is there evidence from other studies to support your claims?
• How do the results support what you expected?
• How do the results support what you already knew about the topic?
• Can you think of alternative explanations for the results?
• Do your conclusions rely on inferences or assumptions that other people would make? Are there important limitations in the research?

How Science Argument Fits with Investigation

Encourage students to see that, hand-in-hand with sense-making, argument happens all throughout an investigation. Scientists’ compliments and critiques of each others work include:

• the best way to set up an experiment
• whether the data collection is done in a valid way
• how graphs and charts should be put together
• what the data mean, which data can be used as evidence
• how strong and important the conclusions are

Support students as they wrestle with resolving conflicting ideas that may emerge through argumentation. Help them see that while scientists may strongly defend a particular hypothesis or idea, if new evidence is discovered that doesn’t fit the theoretical framework, they have three options. In this case scientists (and science students) can:

• Challenge whether the new evidence is valid based on a critique of the experiment that was done to collect it (“but you only exposed those seeds to heat…they had plenty of water, so how can you say that your conclusion applies to seeds growing the Southwest?”)
• Change their thinking to include the new evidence
• Accept that their idea is limited (“OK, so maybe it works one way in sunflowers and another way in peas”).

See also the Arguing from Evidence Resources for Students and Mentors

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Science Argumentation Resources and References

Education World - It’s Up for Debate! This resource on debate formats for elementary through high school classes has links to rules and rubrics.

Llewellyn, D. And H. Rajesh. 2011. Fostering Argumentation Skills: Doing What Real Scientists Really Do. Science Scope 35(1):22-28.

McNeill, K.L. and J. Krajeik. 2012. Supporting Grade 5-8 Students in Constructing Explanations in Science: The Claim, Evidence, and Reasoning Framework for Talk and Writing. Pearson.

Osborne, J. F. 2010. Arguing to Learn in Science. Science 328: 463-466.

Sampson, V. J. Grooms, and J. Walker. 2009. Argument-Driven Inquiry: A way to promote learning during laboratory activities. The Science Teacher 76(8): 42-47.