Policy for Accurate Reading of OMR bubbles on sheet

How to fill OMR Sheets

Common Instructions for MCQ Tests

The software has flexibility to set the response sensitivity for different types of marks. It has flexibility to change the response settings to read even the smallest marks.

Also if required to read some exceptions in the lot and read even a sheet or a bubble that is not in the policy, the software settings can be changed for that particular sheet. However, the users do not prefer to change setting for every sheet.

So, a clear policy should be decided and corresponding Instructions should be written and illustrated properly with diagrams on the OMR sheet and ideally all sheets should be read according to the policy specified in the instructions to avoid any contentions.

Why we need to have standard policy for different cases?

Example: The same OMR software might be used to read patient and employee feedbacks as well as to evaluate competitive MCQ examinations. The pattern of marking allowed is very different in both cases.


Employee or a patient feedback form where they are asked to tick the appropriate rating.

MCQ exam where the students are asked to fill the bubbles properly.

Strict Policy

Accept only proper tick marks that have been made in proper location and of proper size.

Accept marks made as per instruction with reasonable variation within very tight range due to human factor. Read only bubbles that are completely or nearly completely filled, ignore others.

Relaxed Policy Accept any mark that is understood as a response. Accept any mark that is understood as a response.
Default Policy

Default Policy is kept relaxed to the extent possible to keep it convenient for the respondents. Generally Strict policy is not applied in case of Feedback because purpose is subjective.

Default policy is kept strict so that only clear and evident, intentional and purposeful marking is accepted to avoid contentions. Generally Relaxed policy is not applied in case of Test because objective and outcome of test is crucial.

for different policy for different cases…

Why small tick marks are allowed in feedbacks? Feedback is an activity seeking voluntary participation and honest responses. If you make it compulsory or tedious for the respondent, it will demotivate a user to give honest responses.
One cannot expect or dictate a sick patient or a busy employee to put in extra effort to color the circles. Their honest response is important. So to facilitate the user, he is allowed to make convenient marks on the sheet. Moreover, the user has no direct advantage of filling the sheet, so they can be allowed to mark in their own style.

Why small marks are NOT allowed in MCQ exams? Why only full bubbles filling is expected?
Since there is high stake in exams, the candidates try to make all sorts of attempts to take advantage. If we have a relaxed policy to read marks of all sizes, then if the candidate is not sure of the answer, he might intentionally create ambiguity by making a small mark in one of the options. Now if he gets the answer right by fluke, he will expect the mark to be read, and will claim that this is his marked answer. On the other hand, if the answer he marked is wrong, he might argue that, the mark on his sheet was an unintentional slip, or maybe and impression of other sheet in the stack, but he did not mark it.

Example to illustrate 100% Accurate response in according to evaluation policy set by user

See the response below at Default Settings, Strict Settings and Relaxed Settings. The software is always 100% accurate in reading responses in all the defined cases.

Policy Instructions to candidates

Bubble fills in MCQ test sheet Bubble fills in MCQ test sheet Tick Marks in feedback form
Incorrect Method
Correct Method
Incorrect Method
Correct Method
  1. Use only blue/ black ball point pen to fill the circles.
  2. Use of pencil is strictly prohibited.
  3. Circles should be darkened completely & properly.
  4. Cutting and erasing on this sheet is not allowed.
  5. Do not use marker or white fluid to hide the mark.
  6. Do not use any stray marks on the sheet.
  1. Mark boxes like this [==-=] with a thick solid black line. Hide the letter in the box completely. Do not make a thin line. 
  2. Use a dark HB or No.2 pencil only.
  3. Rub out any errors thoroughly.
  4. Mark within the given box, Do not cross margins.
  5. Do not use any stray marks on the sheet.

Variations Observed in Marks on OMR sheet

  Bubbles - Proper Intensity
(Pen/Dark Pencil Filled)
Bubbles – Light Intensity
(Light Pencil Filled)
Tick Marks - Proper Intensity
(Pen Marked)
Proper Impact 1A, 2A, 3A, 4A, 5A, 5C, 7A, 8A, 11A, 12A, 13A, 14A, 15A, 15C, 17A, 18A, 21A, 22A, 23A, 24A, 25C
Shape Variations: 5A, 7A, 15A, 17A -Attempt to cancel response
26A, 27A, 28C  
Small Impact 2D, 4C, 9B, 10A, 12D, 14C, 19B, 20A 29B, 30A 41A, 43A, 45B, 46A, 48A, 49B, 50A, 50C
Shape variation: 50D – Cross mark
Very Small Impact 3C, 4C, 6A, 13C, 14C, 16A, 23C, 24C
Improper erasure: 8D, 18D
29B, 30A
Improper erasure: 22D, 27D
42B, 44B, 45A, 47B, 48B

Software Response at Different Settings as per evaluation policy

Strict Setting for Bubble Relaxed Setting for Bubble Setting for Light Intensity Impact Setting for Very Small impact
Sensitivity : 40 /0 /10 Decreased
Threshold :150 Default
Sensitivity : 30 /0 /10 Default
Threshold :150 Default
Sensitivity: 15 /0 /5 High
Threshold :160 Improve
Sensitivity: 7 /0 /5 Extra High
Threshold :160 Improve

It is IMPORTANT to study following topics:

Understanding Concept of Accuracy for 100% accurate Addmen OMR Software

How Addmen OMR Software can accurately detect OMR marks from an answer Sheet?

How to get Accurate Results from OMR Sheets with Pencil Filling?

How to get Accurate Results from OMR Sheets with OCR/ICR/Barcode blocks?

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