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ABOUT THE GRADING PROCESS (FALL,
2006) |
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Course letter grades will be determined
from the top down by the overall Course Score (CS), calculated from the Normalized Test Score (NTS), the Normalized Lab Score (NLS),
the Normalized Homework Score (NHS), and the Normalized Participation Score, (NPS), as follows: |
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(CS) = 0.55 (NTS) + 0.30 (NLS) + 0.10 (NHS) +0.05(NPS) |
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Here the normalized test score, NTS, is the normalized (See Normalization
below) value of the adjusted test score, ATS, which in turn is equal
to the sum of the normalized scores for best
four of the five course test hours, comprising the two hour final
exam and the three one hour exams.
(See also EXAM
POLICY.)
In other words, the lowest (normalized) test-hour score is dropped for
every student, and the resulting sum, (labeled here ATS) is renormalized
to become NTS before being included into the Course
Score, CS, with the weight, 0.55, specified above. |
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The Laboratory Score, NLS, is computed from the adjusted raw lab score, ALS, obtained from the raw sum of the semester’s lab report grades, RLS, on the basis of “80% of the Maximum” process described below. NLS’s weight is 0.30. |
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The Homework Score, NHS,
is similarly obtained from the adjusted HW score, AHW, obtained from the raw sum,
RHS, of the semester’s HW scores by “80% of the Maximum” process
described below. NHS’s
weight in CS is 0.10. |
| In-class clicker
quizzes related to the course material will also be given from time to
time. Their grades will be totaled to yield the Raw Participation Score,
RPS. By applying the “80% of the Maximum
“ process described below, this raw score, RPS, will be converted into
the adjusted participation score, APS,
whence the Participation
Score, NPS, is obtained by Normalization (described below), as
for NLS and NHS. NPS’s
weight in CS is 0.05. |
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Students whose Course Scores lie in the
top 25% will receive an A. Students whose Course Scores lie in the top 50% will
receive at least a B. The A/B
break-point will be set where a gap occurs in the course scores which is large enough to distinguish the
performance of the lowest-scoring A student from that of the highest-scoring
B student. Therefore, in practice, more than 25% of the students will likely
get A’s. Likewise the precise B/C break-point will be set by such a gap, so
that in practice more than 50% of the students will receive A's and B's. |
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To estimate letter grade equivalents
from normalized scores, note that about 50% of the population falls above the
average normalized score of 70. That average of 70 is therefore near the B/C
letter grade breakpoint. Furthermore, about 25% of the group falls above the
normalized score of 83.6 = 70 + 13.6, which is therefore the expected A/B
breakpoint. Finally, a normalized
score equal to 90 = (Avg + S.D) = (70 +20) will typically place a student in
the top 1/6= 16.7% of the group, quite comfortably within the top 25% who are
promised A letter grades. In practise, no letter grades are computed (apart
from the Early Warning grades based only on the first exam) until the end of
the course, and then they are defined entirely by the course score computed
as prescribed above. |
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Course Requirements |
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Students who do not complete the course requirements will
receive an F. Failure to complete all
of the Labs and submit all of the lab
reports, missing the Final Exam, and/or missing two or more hourly exams
each constitutes a failure to complete the course requirements. Generally
students who do complete the course requirements earn a course score
sufficient for a D. Regarding the C-D
breakpoint, we shall apply a prejudice in favor of C by giving D's only to
students whose course scores are separated by a gap from the smooth
distribution of the rest of the class. Thus despite our prejudice for C over
D, a substantial gap between your score and the low edge of the continuous
part of the class distribution may be dangerous to your C. |
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“80% of the Maximum” is Enough |
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The “80% of the Maximum” process
for adjusting Lab, HW, and Participation components of the Total Course Score
is based on the proposition that the Lab, the Homework and the Participation Quizzes
are learning experiences, which, so long as they meet a certain pre-set
standard, should carry no grade penalty. We consider the achievement of “80%
of the Maximum” possible total score to be “good enough”. In addition, we
believe that “80% of the Maximum” is within the reach of every student who is
willing to expend a reasonable effort. |
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Therefore every student who
achieves 80% of the Maximum possible Homework, Lab, or Participation score will receive the
same highest (=100) Adjusted Raw HW (AHW), Adjusted Raw Lab (ARL), or
adjusted Raw Participation (ARP) score. Students who achieve less than “80%of
the Maximum” will receive a raw score equal to the percentage of 80% which
they achieve. These raw scores will then be normalized into NHS, NLS, and NPS
distributions with an Average of 70 and a standard Deviation of ±20 (just as the adjusted test
scores, ATS, are normalized), to yield the Normalized Lab, Normalized HW, and
Normalized Participation scores, NLS,
NHS and NPS, used to compute
the Course Score, CS, with the
50-30-10-10 weighting given in the CS
formula given above. |
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Be Sure to Achieve the “80% of Maximum” Level |
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Beware: We advise everyone to make sure that he/she achieves the highest
possible Adjusted HW, Adjusted Lab, and Adjusted Participation score,
not just because it guarantees them the highest normalized HW, Lab and
Participation scores, but because the failure to do so may seriously
damage their NHS, NLS, |
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Normalization |
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Before any two grade components are
added, they shall always be Normalized so that their distribution has an average
of 70 and a standard deviation of 20. Thus if a certain (e.g. your own Exam
I, or your adjusted lab score, ALS) grade has a raw (i.e., un-normalized)
value, R, and comes from a class-wide distribution which has an average, A,
and a Standard Deviation, D, the corresponding normalized grade is: |
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Note that this normalization process yields
a new distribution which has exactly an average 70 and a standard deviation
of exactly 20. The process always leaves the rank ordering of the group
unchanged: The top (or the 12th from the top) student is
still the top (or the 12th from the top):
a higher value of R always yields a higher value of N.
But normalization provides a fair mechanism for dropping the "lowest"
of several exam scores, even when one exam may have been much more difficult
(i.e., had a lower class average) than the other exams. Since the normalized
scores' distributions for all exams have, by construction, the same
average (70) and the same standard deviation (20), the effects of any
differences in class averages for the several exams has been removed. |
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We repeat the warning issued already above: if in the original distribution, nearly everyone has the highest possible score, as we expect to be the case for the adjusted HW, adjusted Lab, and the adjusted Participation scores (because of the "80% is good enough" rule, which replaces all scores above 80% of the maximum possible score by the same maximum score = 100) then the few students who fail to meet the 80% threshold may find their normalized score diminished significantly by the normalization calculation. Indeed, the normalized score can sometimes even become negative, although when it does so, we shall intervene and replace the negative score by a zero. This is the flip side of the promise that if you meet the minimal 80% standard, you will earn the maximum credit for HW, Lab and/or Participation: if you do not satisfy this easily achievable threshold, the normalization process may wipe out much or all of your credit for the HW, Lab and/or Participation components of your course grade. |