DORDT COLLEGE ENGINEERING DEPARTMENT

PROFESSOR DE BOER'S METHOD OF GRADING


Is the checkered flag unfair?
Should both drivers get an A?

Photo copyright Piotr Kozlowski,
cropped and used by permission CC BY-SA 3.0


Are the low clearance warning signs (11' - 8") unfair?
Should the driver get a B– or an F?

Photo copyright Jürgen Henn — 11foot8.com,
modified and used by permission CC BY-NC-SA 3.0

THE MAIN THING: Grades predict academic ability
Grades are like road signs telling you what to expect ahead if you keep going as you are. After graduation, will you be able to get the job done? Will you succeed at graduate school if that is your goal? Inflating grades to make it easier to get scholarships and other benefits will not assure that you can do what needs to be done.

"Grades should mean something more than flattery. Grades speak to the world, not just to classmates, parents or a campus. Eventually performance shows and counts, and must be competitive on the merits. I encourage students to sharpen skills now by selecting challenge. . . . When you evaluate courses (or colleges) consider that thoughtful professors do not give grades, they assign them on the basis of the evidence provided by a student's work."
        (quoted from Professor S.A. Miller at Hamilton College, New York State)

Grades are not based on degree of effort or amount of time spent studying, or maintenance of self-esteem. A poor grade on a test or report does not result in a general opportunity to earn extra credit.

Prof. De Boer Curves Grades and Here is Why. . .
Grading rubrics or curves serve to normalize grades so that they can be easily understood by everyone. In the United States, letter grades are the usual means of grading. Here is what the letter grades mean:
A       Exceptionally Good
B       Normal (good enough for graduate school or employment)
C       Graduation minimum (minimally employable in discipline)
D       Unsatisfactory (Some type of change is needed to proceed.)
F       Failure
Plus and minus modifiers may be used, for example "B+" meaning normal but bordering on exceptional. (The grades "A+," "F+", and "F–" will not be used. Those grades will be rounded to the letter.)

Professor De Boer uses the normal performance of all the students he has ever taught in a particular course as the norm, not the class average. This avoids some of the disadvantages of grading on a curve. For example it is possible in Professor De Boer's classes for everyone at the end of a particular semester to get course grades of "A." At least in theory, this would happen if everyone did work that was well above the norm of past students. You can read more about grading on a curve in Wikipedia.

Major Items are Letter Graded
All major items (tests, lab reports, etc.) are ultimately assigned letter grades according to the rubric above.

Letter grades for lab reports are explained in a booklet by Prof. De Boer titled, "How to Write a Lab Report." Test grades are derived from a grading curve which varies from test to test in order to maintain the rubric shown above. Professor De Boer writes tests with a goal of 65 to 70 points out of 100 representing normal performance, or a "B." Professor De Boer realizes his curves are typically about 10 or 15 points lower than the traditional curve of 80% being a "B." In other words, his tests may be harder than average, but he offers a more favorable curve in compensation.

Only letter grades count toward the course grade. When Prof. De Boer calculates course grades he ignores all the raw point scores and other feedback he may have given students. (Exception: If a course grade falls on or very near a borderline, he will consider those and other factors such as class participation when deciding to round the grade up or down.)

Minor Items (like homework) Earn Points
Each minor item is assigned a point value. A homework problem of average complexity and importance will be assigned about 5 points. Problems that are assigned more points are more important or more complex.

The total number of minor item points possible in each of Prof. De Boer's courses is typically about 600 to 700 for courses employing peer grading on every homework assignment and about 350 to 500 for courses that have no peer grading at all. The total depends on how the course actually transpires and thus cannot be exactly tallied at the start of the course.

Points are earned according to the following rubric:

More points than the problem is worth: (e.g. "6/4")
A rare case of exceptional work.
The extra points amount to extra credit, indulgences if you will, to be applied against mistakes on other similar assignments.

All possible points awarded
Equivalent to "A" (e.g. "4/4")
The work is done correctly and written down clearly.

All but one or two points awarded
Equivalent to "B" (e.g. "3/4")
A minor mistake like a missing unit or a sign error.

Half of the points possible
Equivalent to "C" (e.g. "2/4")
A mistake but a reasonable method of solution is evident.

One or two points
Equivalent to "D" (e.g. "1/4")
The method of solution is wrong, but the work is more than piddling.

Zero points
Equivalent to "F" (e.g. "0/4")
The problem was not attempted or the work is piddling.
The points earned for each minor item are added together in a category. For example, "regular graded homework" is a category in each of Prof. De Boer's courses and in some courses, "peer grading" is another category. These points are then applied against a curve to derive a letter grade for the category. The curve is quite simple. Take your total earned points in a category, multiply by four, and then divide by the total number of points possible. Then truncate the result to three significant figures. (e.g. 2.4999999 becomes 2.49) This results in something called grade points. The letter grade is assigned according to the following curve:
4.00–3.75   A
3.74–3.45   A–

3.44–3.15   B+
3.14–2.85   B
2.84–2.50   B–

2.49–2.15   C+
2.14–1.85   C
1.84–1.55   C–

1.54–1.45   D+
1.44–1.35   D
1.34–1.24   D–

1.23–0.00   F
Generally, grade points near 4 mean "A", near 3 mean "B", etc. Notice that the "A" and "D" ends of the curve favor the extreme grades. In other words, you need 2.50 grade points at minimum to get a "B–" but you only need 3.45 grade points to get an "A–". This is done because it is hard for very good students to average an occasional mistake with some even better than perfect work. Instead, the curve is lowered for them. Similarly, it is too easy for a very poor student to gain a few points by guesswork, and so the curve is raised for them. Students in the "B" and "C" range will naturally have some better grades to average with some lower grades so no adjustments are needed for them.

Here is an example.
A student has done nine homework problem sets so far.
The grades on the problem sets are,

12/13, 11/11, 10/16, 7/9, 11/12, 12/13, 17/19, 13/16, and 7/7.

The total points earned are

12 + 11 + 10 + 7 + 11 + 12 + 17 + 13 + 7 = 100

The total points possible are

13 + 11 + 16 + 9 + 12 + 13 + 19 + 16 + 7 = 116

Now (100 * 4)/116 = 3.44827586 which is truncated to 3.44
That curves to a grade of "B+" for the homework category. With just one more point earned, this student would have had an "A–."
In calculation of the course grade only the letter grade for the homework is used.

Grade-Point Based Calculations
Grade points are the numeric basis for calculating the course grade. Each of the letter grades from each category of grades is converted to a grade point value according to this rule:
A   = 4.00
A– = 3.67

B+ = 3.33
B   = 3.00
B– = 2.67

C+ = 2.33
C   = 2.00
C– = 1.67

D+ = 1.33
D   = 1.00
D– = 0.67

F   = 0.00
After conversion to a grade point value, each category grade is multiplied by a weight factor given on the course syllabus. The products are added up and truncated to three significant figures giving a weighted average grade point value for entire the course. That is turned into a letter grade using a curve similar to the one above for homework letter grades. (Prof. De Boer reserves the right to adjust the course curve somewhat, but usually the curve used is nearly identical to the homework curve.) The letter grade that results is reported to the registrar as your grade for the course.

Here is an example:
The course syllabus shows this "means of evaluation:"
Homework 10%, two tests 20% each, lab report 15%, computer project 10%, final exam 25%.

The student has earned these grades:
Homework: A–
Test One: B+
Test Two: A
Lab Report: C–
Computer Project: F (nothing was turned in)
Final Exam: B+

The grades are converted to grade points and then weighted:

Homework: A– → 3.67 → 3.67 * 0.10 = 0.3670
Test One: B+ → 3.33 → 3.33 * 0.20 = 0.6660
Test Two: A → 4.00 → 4.00 * 0.20 = 0.8000
Lab Report: C– → 1.67 → 1.67 * 0.15 = 0.2505
Computer Project: F → 0.00 → 0.00 * 0.10 = 0.0000
Final Exam: B+ → 3.33 → 3.33 * 0.25 = 0.8235

The products are added:

0.3670 + 0.6660 + 0.8000 + 0.2505 + 0.0000 + 0.8235 = 2.9070

The result is truncated to three significant figures, 2.90, and the grade is looked up on a curve (same as for homework). In this case the course grade is "B."
Grade Reports From Canvas
Prof. De Boer uses Canvas to record the grades of each graded item in the course. You may look up your grades in Canvas at any time. However, Prof. De Boer has not figured out a way to make Canvas compute course grades using the system described here. Canvas keeps a good record of your grades on each graded item, but the category and course grades computed and reported by Canvas are not used by Prof. De Boer and thus you should ignore them for his classes.

At the end of the semester Prof. De Boer exports the grades from Canvas to a spreadsheet that has all his methods built into it. That spreadsheet computes the course grades. Then Prof. De Boer manually enters the "CourseGrade" into the grade book at Canvas and submits the grade to the registrar.