[LON-CAPA-users] Re: Bubble sheets

Lars Jensen lon-capa-users@mail.lon-capa.org
Thu, 05 Feb 2009 23:24:57 -0800

Hi Stuart,

Thanks for clarifying this. All we have on our scantron form is the 
student-ID (the same lon-capa's "Student/Employee ID"), an optional 
code, and then the question responses (A to E). The scanner report file 
has this form:

Student-ID Code Responses

tmccphys:TMCC Physics w/CODE:number:11:3:1:9:15:1: :letter

I am not aware of a paper-ID and there's no first- or last name on the form.

Would the above entry be correct for the scantronformat.tab file, or 
should are the last fields required, like this

tmccphys:TMCC Physics w/CODE:number:11:3:1:9:15:1: :letter::::::

or should it be like this:

tmccphys:TMCC Physics w/CODE:number:11:3:1:9:15:1: :letter:0:0:0:0:0:0


Stuart Raeburn wrote:
> Lars,
>>  (a) What is the CODE used for?
> CODE is used in "anonymous" bubble sheet quizzes/exams in which each 
> student receives a quiz/exam with a code (e.g., six letters: each letter 
> one of A through J) in place of the student's name.  This makes it 
> easier to administer the quiz/exam, as it is no longer necessary to 
> match a correct (named) printed quiz/exam to the corresponding student.  
> Instead the students must bubble in the six character code in the 
> appropriate location on the bubble sheet, so that LON-CAPA will grade 
> the student's bubbled submissions according to the version of the exam 
> the student answered (the CODE is used in the randomization when the 
> quizzes/exams are printed).  When using CODEs it is not necessry to 
> print an individual quiz/exam for each student.  If you decided to use 
> say ten CODES you could print ten quizzes/exams (one for each of the 
> CODEs) and could then photocopy each version how ever many times you 
> needed to generate the required total number of quizzes/exams.  To use 
> anonymous quizzes/exams with CODEs your bubble sheet scanning mechanism 
> needs to be able to extract the code (which the student bubbles in on a 
> specific location on the bubble sheet) and include it in the raw data 
> record written for each student in the columns specified according to: 
> CODEstart and CODElength
>> (b) What is Qlength The examples uses a value of either 1 or 10. What 
>> does this mean?
> Qlength is the number of characters in the raw data used to record the 
> student's bubbled answer for each row on the bubble sheet.  If the raw 
> data indicate bubble position by a letter or a number (e.g., A = first 
> bubble or 1 = first bubble etc.) then the number of characters would be 
> 1 (assuming 10 bubbles or less for the number case).  If however, bubble 
> position is indicated by position of the Qon (bubbled) character, then 
> each bubble row might have 10 characters (one for each of the 10 
> possible positions with Qon at the position bubbled and Qoff elsewhere, 
> (e.g. if Qon = 1, Qoff = .  the portion of a student's record for a 
> single bubble row might be:  ...1......  indicating position 4 was the 
> one bubbled.
>> (c) What is Qon and Qoff? Qoff seems to be empty in the examples. Is 
>> Qon    designed to explain to lon-capa any discrepancy between the 
>> labeling of lon-capa question options and those on the scantron form?
> Qon is the character used in the raw data generated by the bubble sheet 
> scanner to indicate a filled-in bubble.  This could be the corresponding 
> letter (A - J), or number (1,2 ... 9,0) to indicate which bubble was 
> filled, or in the positional case might be a character (e.g., 1) to 
> indicate the presence of a filled bubble.  Qoff is the character used to 
> indicate an unfilled bubble, this is commonly a single blank space.
>> (d) What are PaperID and PaperIDlength
> PaperID is an identifier which the bubble sheet scanner generates for 
> each sheet scanned (some hardware prints this on the bubble sheet when 
> scanning it so that you can match the raw data to the corresponding 
> paper, in case there is a question over multiple bubbles or undetected 
> bubbles on a single bubble sheet row). The PaperID is included in the 
> raw bubble sheet data at the column position defined by PaperID.  
> PaperIDlength is the number of characters used for this identifier.  
> LON-CAPA reports the PaperID (if defined) where a bubble error is 
> encountered (double bubble, missing bubble etc.) ans also uses the 
> PaperID in cases where each CODE is only to be used once, i.e., each 
> student receives a unique quiz/exam.
> For completeness, below is the text included in the bubble sheet config 
> comments in /home/httpd/lib/perl/Apache/grades.pm (the LON-CAPA module 
> used for grading using bubble sheet raw data files):
>       name         - internal name for the this configuration setup
>       description  - text to display to operator that describes this config
>       CODElocation - if 0 or the string 'none'
>                           - no CODE exists for this config
>                      if -1 || the string 'letter'
>                           - a CODE exists for this config and is
>                             a string of letters
>                      Unsupported value (but planned for future support)
>                           if a positive integer
>                                - The CODE exists as the first n items from
>                                  the question section of the form
>                           if the string 'number'
>                                - The CODE exists for this config and is
>                                  a string of numbers
>       CODEstart   - (only matter if a CODE exists) column in the line where
>                      the CODE starts
>       CODElength  - length of the CODE
>       IDstart     - column where the student ID number starts
>       IDlength    - length of the student ID info
>       Qstart      - column where the information from the bubbled
>                     'questions' start
>       Qlength     - number of columns comprising a single bubble line from
>                     the sheet. (usually either 1 or 10)
>       Qon         - either a single character representing the character 
> used
>                     to signal a bubble was chosen in the positional 
> setup, or
>                     the string 'letter' if the letter of the chosen 
> bubble is
>                     in the final, or 'number' if a number representing the
>                     chosen bubble is in the file (1->A 0->J)
>       Qoff        - the character used to represent that a bubble was
>                     left blank
>       PaperID     - if the scanning process generates a unique number 
> for each
>                     sheet scanned the column that this ID number starts in
>       PaperIDlength - number of columns that comprise the unique ID number
>                       for the sheet of paper
>       FirstName   - column that the first name starts in
>       FirstNameLength - number of columns that the first name spans
>       LastName    - column that the last name starts in
>       LastNameLength - number of columns that the last name spans
> There is also some discussion of bubble sheet exams in the Course 
> Coordination Manual (section 19: Scantron Examms - page 65).
> Stuart Raeburn
> MSU LON-CAPA group
>> Thanks Stuart and Ray for answering these questions. I still hae a 
>> couple of questions on the fields in scantron.tab:
>> (a) What is the CODE used for?
>> (b) What is Qlength The examples uses a value of either 1 or 10. What 
>> does this mean?
>> (c) What is Qon and Qoff? Qoff seems to be empty in the examples. Is 
>> Qon    designed to explain to lon-capa any discrepancy between the 
>> labeling of lon-capa question options and those on the scantron form?
>> (d) What are PaperID and PaperIDlength
>> Thanks so much for your help.
>> Lars.
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