Percentages don’t have the power to express a grade.

The traditional model for grades in a class lacks the flexibility required to reflect what I really think of a student.  When I used weighted categories (e.g. 50% exams, 30% homework, 20% class participation), I found that some of the students passing my class didn’t really seem to deserve it, and some of the students failing my class really should have been passing.  “Well, adjust your weights,” you say, and that’s a good idea: I made several improvements and was progressively more satisfied with my results.

But.

One test of the 29 I’ll give this semester deals with simplifying exponential expressions.  If a student gets 100% on each test except the exponential simplification test, on which he gets a 0%, his average will be 96.5%, A+, Honors.  He doesn’t have to worry about exponential simplification at all, and he can just move on and never learn it.  I’m not suggesting that this hypothetical kid be made to retake Algebra 2, of course.  I’m suggesting that he be required to learn exponential simplification.

So, in my class, I require that every student earn at least a 3/5 on every single skill that we study.  Then, I require an overall average of 75% on top of that minimum requirement.  Students get some leeway, and they do not need to master every single subject (I understand that there are time constraints involved in my students lives, and that they may not really care about my class).  However, they can’t just do well on a lot of skills and decide they’re not even going to bother with one.  I am not willing to send a kid who can’t simplify exponential expressions at all to the precalc teacher.

The same philosophy can extend to homework.  If you think homework is vital, make it a requirement of passing.  If you don’t think it’s vital, don’t.  Averaging test scores with homework scores is harmful because it dilutes the meaning of your tests and the meaning of your homework.  Averaging mathematically destroys information!

At my school we only have three grades, Pass, No Pass, and Honors.  Each grade has certain clearly stated requirements that I give the students at the beginning of the semester.  I think that a teacher using letter grades could more clearly define what a C was and what an A was by stating the objectives vital for that award than he or she can by trying to come up with a formula to fit every student.  We shouldn’t be afraid to use some criteria that cannot be expressed with percents.

5 thoughts on “Percentages don’t have the power to express a grade.”

  1. I really like this idea, Riley, of emphasizing some essential ideas within a math course. At my school, averaging scores (even if they’re related to learning targets) is almost inevitable because of the student information (PowerSchool) that we are required to use.
    Weights – yes.
    Entering scores that don’t actually count towards the final grade – yes.
    Using median, mode or another creative way to calculate the final grade – PowerSchool won’t do it.
    Requiring a 3/5 – again, this idea isn’t “friendly” with PowerSchool. Hmmm
    Because standards-based grading already bucks the norm, adding on another “layer” of complexity. Is it worth trying? You might have me convinced. After all, implementing standards-based grading was against the status quo. Why not go one step farther? Thanks for sharing your ideas.

    P.S. At Scattergood, must you use a student information system? I see it as a double-edge sword.
    Good: Parents stay informed via the web; consistent among teachers
    Bad: situations like this one: adding ‘soft’ grade requirements and bucking the average tradition.

    Yuck

  2. At Scattergood we do not have a standard student information system. I’m sure parents wish we did, and frankly I long for one at different intervals. Easy parental communication is one reason I’m writing my own grading software (although it’s getting hard to continue in the face of some excellent options I keep discovering). But, right: more important than clear communication with parents is clear communication to kids: XYZ is what’s most important in this class, and you need to do TUV to earn a passing mark.

    And I just can’t live with a single average number determining a student’s grade! (obviously the grade is one single demarcation of a student’s hundred+ hours of work, but let’s not even talk about that here)

  3. What I do is I select the core curricular areas I want them to know and I make THOSE the categories. For example, in Science 9, I make 4 categories: Chemistry, Electricity, Reproduction, and Space. Each is 20% (Final Exam is 20%). Within each category I have 2 weightings – “Formative 0%” and “Summative 100%”. Formative is essentially not worth marks but I record a mark for tracking purposes. Examples of Formative are things like homework checks, practice assignments, quizzes – basically anything I consider practice. Summative would include Unit Tests, projects, assignments – anything I would consider a demonstration of skills after the practice. This has worked out well because students can see which areas (of the 4 sciences) they need work on and they are not punished for practicing. Also, you could tell them that they must get a certain mark in each of the 4 categories in order to pass your course.

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