MDCAT OMR sheet: bubbling rules and costly mistakes

The examiner does not read your booklet. The machine reads the sheet. Your mark comes from the bubbles, not from the working in the margin.

Two candidates can have the same answers and different scores if one fills the sheet badly. Treat the sheet as part of the paper, not as paperwork after it.

The sheet is the answer

The OMR sheet is a machine-readable form. Each row belongs to one question. Each column belongs to one option. The machine looks for a dark mark in one column on each row.

A correct answer in the booklet is invisible if the row is blank. A correct answer in the wrong row is a wrong answer.

The sheet also carries your identity. A sheet with the wrong roll number can be rejected before marking starts. Fill the header with the same care as the answers.

The sheet is the only record the machine keeps. The booklet is collected, but the sheet is what is scored.

Fill the header first

Fill the roll number, paper code, centre code and signature before you open the booklet. Copy the number from the admit card, then read it back digit by digit.

If the sheet has a version code, copy it exactly. A version code tells the machine which paper you sat. A wrong code can make a correct answer look wrong.

Do not write the roll number in the answer grid. Do not use the answer grid for working. Keep the grid for bubbles only.

Check your name if it is printed. If the print is wrong, raise your hand before the paper starts.

If you arrive late and the header is not filled, fill it before you read question 1. A correct answer on an unidentified sheet is still a problem.

How to bubble

Use the pen or pencil the notice allows. Fill the circle fully. Leave no white inside.

One option per question. Do not tick, cross or underline. A tick may read as a mark in the wrong column, or as no mark at all.

Keep marks away from the black timing marks on the edge of the sheet. Do not fold the sheet or crease the corner. A crease can move the paper under the scanner.

If you fill a circle and the pen slips, stop. Fix the row before you move on. A small slip is easier to repair now than in the last five minutes.

Do not use a highlighter on the sheet. Do not write notes in the answer grid.

Alignment: the every-ten check

After question 10, 20 and 30, check the row number against the booklet. Say the number to yourself. Point at the row.

If you find a shift, stop. Count back to the last row you are sure about. Fix the rows one by one. Do not erase a whole section in panic.

A one-row shift can turn 30 correct answers into 30 wrong ones. The answers were right. The rows were wrong.

The check takes about five seconds. It is the cheapest insurance on the paper.

The errors that cost the most

1. A one-row shift. It can cost a whole block. Fix: the every-ten check.
2. Two bubbles on one row. The machine may read the row as invalid. Fix: erase fully before you move on.
3. A faint mark. The scanner may miss it. Fix: fill the circle until the centre is dark.
4. An eraser smudge. A grey mark can read as a second answer. Fix: use a clean eraser and brush the dust away.
5. The roll number in the answer grid. Fix: keep the grid for answers only.
6. The wrong paper code. Fix: copy the code from the booklet, then check it.
7. Stray marks on the edge. Fix: keep the margins clear.

Each error is small at the moment. Each one can cost more than a hard question.

The list is ordered by cost, not by frequency. A shift costs a block. A smudge costs one row. Fix the shift first. Check the rows around a fixed error too, because a slip often marks two rows.

Changing an answer

Use a clean plastic eraser. Lift the sheet slightly. Erase until no grey remains. Do not wet the paper.

If the sheet tears, raise your hand and ask for a replacement. Transfer your answers one by one and check each row. A replacement sheet costs time, but a torn sheet can cost the paper.

Do not erase a whole section because of one mistake. Fix the row, then check the rows around it.

If the paper fibres lift when you erase, stop rubbing. A small fibre can lift the print, and a lifted print can read as a mark.

Batching versus filling as you go

Filling each answer as you solve it is the safest method. It costs a few seconds and prevents a backlog.

If you batch, batch five. After five, check the row number. Do not batch 20, and never leave the last 20 answers for the final two minutes.

The sheet is not a place to save time. The time you save by batching is smaller than the time you lose fixing a shift.

If you are left-handed, check that your hand does not drag across the previous row. A spare sheet under your wrist can help if the centre allows it.

Practise with a real sheet

Print a sheet with 180 rows. Sit a full paper and fill it. Time the bubbling.

Measure your own bubbling time. Some candidates lose more time to erasing than to reading. The only way to know is to measure.

Time a sheet fill with no questions: 180 bubbles. That number is your floor. Then add the reading time.

Use past papers with a printed sheet. Use practice for short sets when you want to drill the sheet without a full paper.

Try one paper with the pen you plan to use. A pen that smudges on the sheet is a problem you can find before the test.

Ask someone to check one page of your sheet against the booklet. A second pair of eyes finds shifts you stop seeing.

Conduct rules that can end your paper

Devices, talking, looking at another candidate's sheet and writing after the stop signal are the common risks. The notice sets the penalty for each.

Do not assume you will get a warning first. Ask the invigilator before you do something the notice does not clearly allow.

If you finish early, check the sheet. Do not leave until you are told. Do not pass anything to another candidate, even an eraser.

The hall rules exist so that one sheet can be matched to one candidate. A breach can end the paper before the answers are read.

The last five minutes

Count the rows you have filled. If a row is blank and the instructions allow a guess, fill it.

Check the last 10 rows against the booklet. The end of the paper is where a shift is easiest to miss.

Do not start a new question in the last minute. A half-read question can produce a wrong bubble on a row you already checked.

Hand the sheet in when told. Keep your admit card. The paper is over, but the result still needs your roll number.

A sheet with 180 dark rows and no stray marks is the goal. Everything else is a question you can answer or leave. For the timing method that keeps the sheet moving, read the exam strategy hub.