Optical Mark Reading Service

The Office of the Registrar at Northwestern University provides OMR scanning of exams and surveys to faculty members and their assistants.

We scan simple multiple-choice tests and return both the answers the students chose, as well as the number correct. We do not provide statistical anaylsis for exams.

OMR Scan Results
The scanning process produces two fixed-length field plain ASCII text data files:

One data file reports name, ID number and number of questions correct
A second data file reports for each student a row with a scanning serial number, name, ID, additional individual data as collected, individual answers to each question and again, a final tally of the number of correct answers for each student

Both files can easily be imported into statistical software or Microsoft Excel for analysis and record keeping. See instructions for importing OMR files into Excel.

We offer the NCS General Purpose Answer Sheet 4521 for 200 questions or fewer. We offer scanning for this form only. This form is available from the Office of the Registrar for $.10 each. Each scanned form is imprinted with a serial number, date and number correct during the scanning process. To order answer sheets, send an e-mail to the address below, include your contact information, quantity and your chart string for billing.

Make an Appointment
The OMR Scanning service is offered by appointment only. Scanning service appointments are offered at 15-minute intervals between 9-11 am and 1-4 pm. When you make your request for an appointment, please choose the time you would like. If your desired appointment slot is taken, you will be offered the closest possible time. You may take that slot, or request another. Please allow three business days lead time for scanning appointments. Bring a USB drive or CD-R to transport your data files, or we can e-mail them to you

E-mail Bill Berry at w-berry@northwestern.edu to make an appointment. Please provide the following information in your e-mail:

Desired appointment time during the scanning hours (e.g. 9:15-9:30)
Instructor's name
School
Department
Course's name
E-mail and phone number for the instructor

About OMR Technology
OMR detects the absence or presence of a mark, but not the shape of the mark. Software interprets the output from the scanner and translates it into the desired ASCII output. Forms are scanned through an OMR Scanner. The forms contain small circles, referred to as "bubbles," that are filled in by the respondent. OMR cannot recognize hand-printed or machine-printed characters. An image of the form is not created by the scanner.

Please take care in handling the answer forms, folds, tears, stains and irrelevant pen or pencil marks impede scanning and can result in a failure to read.

Forms
OMR forms are very specialized documents. Timing tracks along one edge of the forms indicate to the scanner where to read for marks. OMR forms also contain ID marks, which look like black boxes on the top or bottom of the forms. Additionally, tehcut of OMR forms is extremely precise and the bubbles must be located in exactly the same location on each form.

Accuracy
With a quality printed document, OMR technology can consistently provide 99.9% accuracy on read data.

Steps for Importing OMR Files into Microsoft Excel
Note: You will be provided with two data files, filename.dat and FILENAME.SDF
The *.dat file is the larger file, it consists of (1) scanning serial number (2) student's name (3) ID number (4) individual answers (5) number correct
The *.SDF file consists of (1) student's name (2) ID number (3) number correct

Open MS Excel
Choose Open from the File menu
For the Files of Type dialog box, choose All Files (*.*). Select your data file, e.g. the "filename.dat" file
The Text Import Wizard - Step 1 of 3 opens. Choose Fixed width and click on the Next button
The Text Import Wizard - Step 2 of 3 opens. Set column breaks using the lines with arrows. For individual answers, you need to place a line with an arrow between each answer to separate them into columns. Note: There is a long space between the individual answers and teh correct answer count column. When you're finished setting column breaks, click Next
The Text Import Wizard - Step 3 of 3 opens. Click the Column Data Format radio button. Highlight the first column with your mouse, scroll the columns to your right, hold down the shift key and click the final column. Click Finish
In the spreadsheet, select all, and then select the Format menu>Column>Autofit Selection
Save your spreadsheet file