Link Evidence to a Claim

Does the Evidence Support a Claim?

After demonstrating how to create a claim, the teacher shows the students how to link a piece of evidence to the claim. He explains that when the evidence is sitting in the Evidence Bin, it is neither positive nor negative; it doesn’t support or go against the claim. It’s neutral. But when they bring the evidence over into the Claims Workspace, then they need to make a judgment call. Now they are evaluating the evidence to see if it helps or hurts their claim. Sometimes a piece of evidence could even be used to support or oppose the same claim! It depends on how they interpret and discuss the evidence.

He demonstrates how to move the first piece of evidence to the claim and asks where it should go. Does this evidence support or weaken the claim? Most students say it helps the claim; a few say it hurts the claim. The teacher asks to hear their reasoning. One girl explains that you don’t know how much radon is in the air. Another student says that Sally’s house is covered in rock and that radon can be seeping into the house from the rock adding to the fact that this evidence supports the claim.

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The teacher tells them that they are both right. Their arguments will depend on how they interpret the evidence and explain their claims. At this point, he shows them how the evidence opens up a third pane when it is attached to either the supporting (green) side of the claim or the opposing (red) side of the claim.

Just as they discussed how to rate the evidence quality, they again decide how to determine the rating for the support or opposition of the claim. The teacher explains that they’re only evaluating how this one piece of evidence supports or opposes the claim. When making this rating, they are not to consider how reliable the source is or whether they think the evidence is true—that assessment was done in the earlier rating (Rate the Evidence). So assuming for the moment that the evidence is true, how well does it support or oppose the claim? The students agree on the following elements of the rubric:

• One plus sign or minus sign: The evidence doesn’t do much to strengthen or weaken the claim. The claim would be almost the same without it.
• Three plus signs or minus signs: It does help to build the case (or build a case against it), but it’s not a really important piece of evidence.
• Five plus signs or minus signs: The evidence makes a very strong case for the claim (or case against the claim).