Convincing Arguments Come from Evidence and Reasoning

A convincing argument for a new idea backed up with strong evidence is the driver of growth and change in accepted disciplinary knowledge. This is a fundamental aspect of how the scientific enterprise works.

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Students in science classrooms have often had more experience with exploration and experimentation than they do explanation and argumentation. It’s no surprise then that students struggle with constructing evidence-based conclusions and justifying their explanations. But recent research provides some concrete directions educators can take to help their students build these skills.

What is Evidence?

It can be tricky for students to see the difference between data and evidence. After all, 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 is used to support or refute a claim is the evidence.

Subtleties of relevant, reliable, and valid data that 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 to help students think about what the evidence means, particularly in middle schools. Such charts usually begin with 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 are to help students frame a particular claim based on a particular piece of evidence and to make discordance between these more evident.

Regardless of whether the teams you work with use this template, encourage your student teams 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 findings but also their generalizability.

See the Student Arguing from Evidence and Teacher Arguing from Evidence guides for this stage.

Tips for Mentors

• 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?