ppt - Lon Capa

Simon Fraser University
Burnaby Mountain Campus
Beyond Homework
Ray Batchelor
Uwe Kreis
In Chemistry at Simon Fraser University the main use of
LON-CAPA is in the high enrollment courses with a numeric bias.
Weekly personalized lecture or pre-lab assignments with multiple
tries, and both feedback and open discussion are the norm.
Multiple choice bubble sheet exams are also in general use in the
first year courses.
The main motivation is to reduce marker workload.
Another area in which enrollments seem high enough to warrant
automated grading are in the first organic chem courses.
We have not yet seen a demand for online organic chem lecture
assignments. However, we have been running simple organic chem
prelabs for several years. In the last year we have been
experimenting with semi-automated Lab Reports or Dry-labs in
organic chem.
Only a few essay-type responses need to be manually graded.
An Organic Chem Lab Report
Conditioned Sequence
Student chooses own
starting material.
Next 5 problems depend
upon this choice.
Parts shown “1-at-a-time”.
Default feedback suppressed
in some, augmented in others.
Simple Linear
Sequence with
blocking conditions
at key points.
Complementary condition
on alternate pathways to
sequence “Finish” needed
to maintain continuity with
rest of Main sequence.
Effectively produces
unidirectional, single
continuous pathway at
any given moment.
Blocked until “maxtries” is
reached for last part of
preceding problem.
Effectively hides the rest of
the sequence.
For problems preceding a
blocking condition, problem
parts are shown one-at-atime, so that the block is
only removed once all parts
become closed to further
Grading for second part depends upon response to first part.
Result can be 2,1, or 0 points interdependently upon both the individual
limits and on the range.
e.g. p-bromoacetanilide
Lit. mp 167-169 °C
1st Part: 1 point if
(162 °C ≤ “upper” ≤ 169 °C)
2nd Part: 1 point if (0 °C ≤ “upper”-”lower” ≤ 5 °C)
(155 °C ≤ “upper” ≤ 169 °C)
62% of students score 2/2
33% score 1/2
5% score 0/2
Default system feedback is suppressed. However, submitted
JME drawing is redisplayed and an optional second try allowed.
Used in a two-part question where the second part is an essayresponse
explanation of why anisole is an ortho/para director. The submitted drawing is
redisplayed, maxtries=3, and the correct/incorrect status is shown to allow a fair
chance to get the essay points.
Mis-calibration of
pointer, on rare
occasions, is an
issue with
0-point question
with unlimited
tries, allows nocost chance to
see how “clickon-the-image”
No more
Next 3 “click-on-the-image” parts chosen from
bands associated with :
N-H stretch;
aromatic C-H stretch;
N-H deformation; aromatic C=C stretch;
C-N stretch;
aromatic ring out-of-plane bending.
Final Mark Distribution
“From the students we hear
Electrophilic Aromatic Substitution Experiment very little; usually only if
Lab Report (Spring 2007)
they messed up. So that is
good news as far as I'm
concerned. It means that the
questions are well coded,
are clear and make sense to
them. For us, it's a really
big time saver… it saves
time on marking reports.
Even the essay questions
are easier and faster to mark
in the Loncapa system. That
frees up time for the TAs to
do more cheating checks.”