Lessons · Teaching · what a result can and cannot tell you

What a result can say, and what it cannot

A result supports or fails to support the idea being tested, within the conditions that were tested. It does not prove the idea, it says nothing about conditions that were not tested, and two things happening together does not establish that one caused the other.

Hone is a place to practise a career, one idea a day. This is one of its lessons, written out in full and free to read without an account.

In beta. This lesson was written for Hone and has not yet been checked by a state certification officer. Practice material, not professional advice. What that means.

What it is for

This is the honest end of the scientific method, and it is what separates a conclusion from an opinion with a graph attached. A class that learns to say 'in this test, under these conditions' has learned the most transferable thing in the subject.

How to think about it

Write a conclusion in three parts: what the evidence showed, the conditions it held under, and what would be needed to say more. If a result contradicts the prediction, that is a result and not a failure, and saying so out loud is what makes a classroom safe to be wrong in.

Worked example

The evidence supported the idea, in this test, over two weeks, on these seeds

Bounded by the conditions that were actually tested.

It does not prove it: the next test could disagree

Science does not prove; it fails to disprove, repeatedly.

Ice cream sales and drownings rise together, and neither causes the other

Both follow hot weather. This is the example every pupil remembers.

An unexpected result is a result, not a mistake

The experiment worked. The prediction was wrong, which is information.

Your turn

Name what two things rising together does not establish.

Things happening together does not show that one  the other

The trap

Writing 'this proves' in a conclusion. It supports, it is consistent with, it fails to support. Proof belongs to mathematics and a science classroom is the right place to say so.

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