[LON-CAPA-admin] Scantron grading problems
raeburn at msu.edu
Thu Apr 10 18:01:44 EDT 2008
When the raw data file was re-uploaded, it will have overwritten any
existing file (if indeed one was written to disk during the initial
(failed) upload attempt, if you used the same file name. The scantron
grading screen provides an interface to download scantron data files
uploaded to a course - the "Download: Show List of Associated Files"
button, so this could be used to compare the raw scantron data file
with the original data file provided by your scoring office.
LON-CAPA does not currently provide a mechanism to "wipe out" all
grading information for a particular problem instance in a course.
However, regrading a sequence using scantron grading will cause new
submissions to be recorded for each student, and the last submission
will be the one which determines the correctness, and the points
awarded to each student for each problem part. A side effect of
regrading via scantron is to increment the number of tries (i.e., the
number of tries for each problem part would become two, which might
seem odd for a scantron exam).
My recommendation would be to download the existing raw data scantron
file, copy it, and then remove all except the record for one student.
Upload this "reduced" scantron data file to the course with different
name, and then regrade with this file (this will cause new submissions
for just that student). You'll then be able to compare the submission
history for that one student, to see whether the regrading made a
difference, particularly for problem 14 onwards. If regrading appears
to resolve the issue, you can then regrade for the remaining students.
If the issue is not resolved, if you can provide me with temporary CC
access to the course, and send me the contents of
/home/httpd/lonTabs/scantronformat.tab on the server where scantron
grading has occurred, I can work with you to resolve the problem.
I have recently worked on a utility to allow a course coordinator to
compare the raw scantron data record for each student, with the
corresponding submission record stored for that student by the
scantron grading process (it compares the last submission data). This
utility will report any discrepancies found (and which students are
affected), and is expected to appear in some form in 2.7. Contact me
off list if you'd like to have a pre-release version of the utility
run for this particular exam.
MSU LON-CAPA group
Quoting Todd Ruskell <truskell at mines.edu>:
> We're having some problems running some Scantron exams with version
> 2.6.2. At some point while uploading the scantron file the first time,
> LON-CAPA spit out a long error report (I can send it on individually if
> people are interested). Apparently it did this without
> notification to the instructor. Additionally, at some time during the
> initial upload, the client machine got rebooted.
> A second attempt to upload scores resulted in no apparent errors.
> However, when looking at the exam statistics, after about question #15,
> the number of responses quickly diminishes, and LON-CAPA reports no
> students out of 493 got the last question (#22) correct. In looking at
> the raw scantron file, the statistics on these last problems are not
> So the question: It appears that something probably has gotten
> corrupted, but what? Is it possible to relatively easily wipe out all
> grading information for this exam and start over? In the exam all
> problems have 5 responses except #14 and #15, which have only 4
> responses. But we've done that kind of thing before, with no problems.
> I should also point out that an exam in a different course was graded
> with no apparent problems the same day.
> Thanks in advance,
> Dr. Todd Ruskell
> Senior Lecturer, Department of Physics Office: Meyer Hall 326
> Colorado School of Mines Phone: 303-384-2080
> 1523 Illinois Street Fax: 303-273-3919
> Golden, CO 80401
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