Monday, April 1, 2013

SBG Part 2 - Grading Scales

I grade students on a 0-4 scale based on their level of knowledge or ability on learning goals that are written as "I can" statements in student-friendly language.

At the beginning of the course, I have them glue my grading policy into their science notebook.  It contains the following rubric:

Score Description
4 Expert  - My response shows I understand the content/ skills completely and can explain them in detail.

 (This means no mistakes on an assessment, or only a very minor error)
3 Proficient - My response shows I understand the important parts about the content/skills.

(This means only minor errors on an assessment)
2 Developing - My response shows I have a general understanding of the content/skills, but I’m also confused about some important parts.

(This means that it's obvious to me that the student understands some of the material, but is also confused about some of it)
1 Beginning - My response shows I have minimal understanding of the content/skills.

(This means that it's clear that the student understands very little about the concept)
0 No Evidence - My response shows I have no understanding of the content/skills

(This means that the student clearly understands nothing or close to nothing about the concept)

I also provide students with a chart in the grading policy that allows them to convert their 0-4 scale grade to a letter grade.  In the chart below, I have included that information, plus the minimum percent for each grade bin.

A+ 4.00 100
A 3.99 - 3.80 95
A- 3.79 - 3.55 88.75
B+ 3.54 - 3.20 80
B 3.19 - 2.85 71.25
B- 2.84 - 2.55 63.75
C+ 2.54 - 2.20 55
C 2.19 - 1.85 46.25
C- 1.84 - 1.55 38.75
D+ 1.54 - 1.20 30
D 1.19 - 0.85 21.25
D- 0.86 - 0.55 13.75
F 0.54 - 0 0

There's no formula that you can use to convert a 0-4 scale to a percent scale.  I have tweaked my scale a few times over the last couple years.  You can check out the excel file that I use to work on the scale.

My grade bin sizes are not exactly equal, but it's the best I have been able to do so far.  There are two factors that drive my bins:
  • I want a score of 3 to equate to a grade of 'B', so that means a middle 'B' must be equal to 75%.  Similarly, 2 should be 'C' and 1 should be 'D'.
  • If a student assesses two standards, and earns for instance a 3 and a 4, I want the scores to average out to 'B+', not 'A-".
Speaking of averaging out, I am limited to a traditional online gradebook called i-Cue.  While I would like to eventually have tiers of standards where some standards are weighted more heavily than others, I feel that it would get too confusing for students and parents.  

All standards are in one category that counts toward 100% of a student's grade during most of the semester.  I have a comprehensive end-of-semester final that I weight as 10% of the semester grade, so the academic standards end up being 90% of their grade.

Our online gradebook defaults to the standard 90-80-70-60 scale, but teachers can edit the percentage bins as they please, so I can warp the gradebook enough to achieve my basic needs for SBG.

I can also suppress the percentage score that students and parents can see.  I do this because parents and students are not used to seeing a score of say, 50% to equal a 'C'.  Percentages have a different meaning in my class and it's not important information for students or parents.

If you use i-Cue in your school district and would like me to help you set up i-Cue for SBG, I'd be happy to help!  :)

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