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Grading Geometry Proofs

Question from Derek:

I am considering your Geometry program for our children. However I am not convinced yet that I could grade geometric proofs fairly, consistently and accurately. Since proofs have mutiple possible correct answers depending on how the student writes them how do you recommend grading them? And do you provide any help with that or direction in that regard for parents? While I did well in Geometry myself ‘way back’ in the day I am by no means a mathametician either. And I want to be fair to my children. I know you say your program is not ‘proof intensive.’ But since Jacobs covers proof I would think you do as well, correct?

Thanks for any input you can provide regarding correctly handling and grading geometric proofs.

Answer from Dr. Callahan:

The way the text handles proofs is quite different. Instead of long proofs, they tend to be broken into stages of a though f (or however long they need to be).

The result is that there is not as much confusion as you might expect.

So here is how we grade.

– Each problem on the test comes straight out of the book
– The solutions manual is used to grade the tests.
– Each problem is graded either right or wrong – not partial credit.
– Any problem missed is reworked by the student for some partial credit back.

The reason for this method — you learn from your mistakes. Second benefit is that grading is easier.

So, if there is that one problem that they got different from the book, then the rework is a time to look at it. If it applies, full credit should be given.

At times we get parents who ask about these problems to our support line at support@askdrcallahan.com. But there is very few of those.

So for you it might show up 2-3 times per the course – so very doable.

Hope this helps.

dwc