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Question

As our district struggles with transforming our grading and reporting practices, the subject of zeroes continues to be tenuous. Recently a teacher shared the following analogy... what's your take?

"I will continue to have trouble with no grade is less than __% (in place of a zero). Continuing with the real world analogies - not changing the tires of my car is 0 tires. This would not be an acceptable business practice. If we are following a business model of inputs and outcomes then telling me that I have 50% of my tires when I do not is unacceptable. How can we reconcile this?"

2013-01-19
MNS
 

The
Grade
Doctor
says:

Not a reasonable analogy. The basic problem with zeros is their use with the calculation of
the mean in unequal difference scales. If your district uses the most common grading scale
- A - 90-100%, B - 80-89, C - 70-79, D - 60-69 and F - below 60, a zero is not an F it is
a K. Also we teach in grade 5 math that the mean is an inappropriate measure of central
tendency when there are outlier scores and zero is the ultimate outlier. If you change to a
50 point scale with five 10 point groups or a 4 or 5 point equal difference scale then your
colleagues analogy is more reasonable and you can use zeros but NOT when you are usin
an unequal difference scale.

 

 

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