Scantron'nomics

If you've taken a standardized test in the past thirty years, chances are you're familiar with the Scantron form: the blank slate of bubbles that can either be your best friend or worst enemy depending on your level of preparation. Whether it's something as important as the SATs or just an everyday exam in Psych 101, your ability to navigate a Scantron will impact your ultimate level of success. So, whip out that pencil and get ready to jot down a few quick notes, because this is everything you need to know about Scantrons.

Traditional Scantron tests typically involve multiple-choice questions in which the test taker must fill in the bubble to denote each correct answer. Once the test has been completed, the sheet is run through a Scantron Machine, which uses optical mark recognition to check each bubble and tabulate the results. First an answer key is fed through or entered into the machine, and this answer key is matched up against each subsequent sheet run through the machine, marking incorrect answers and producing a total score for each exam.  

Why a #2 Pencil?
The requirement of a #2 pencil is somewhat a misnomer.  The #2 constraint is mostly due to historical conditions.  Back in the day, marks were scored by shining a light through Lucite paper; the bubbles that blocked the light counted as the marked answer.  Graphite is shiny to reflected light, and opaque to transmitted light (unlike blue or black ink). The softness of a #2 pencil left the perfect amount of Graphite behind (#3 & #4 pencils had too many marks missed). 

The #1 pencils could leave too much Graphite behind, and could smudge (especially on hot & humid days).  Today’s Scantrons can view #3 & #4 pencil marks and can usually decipher a deliberate #1 mark from a smudge, so don’t fret if you find yourself with a non #2 pencil next test around!

Breakdown of Methods

Because Scantrons limit the scorer's involvement in the grading process, there are opportunities to try fooling the machine in an attempt to get credit for a question you simply don't know. (The success rate is low and you may have a good chance of these being noticed by your teacher)

Some of the most common methods are as follows:

1) Marking or Erasing the Black Lines

If you have taken a close look at a Scantron sheet, you may have noticed black bars running along the left side of the form and corresponding with each question. By either darkening or erasing the black bar for the question you don't know the answer to, you can sometimes cause the machine to skip over the answer and mark your lack of response as being the correct choice. This is reported to have no more than a 30% chance of success, so it's really only slightly better than guessing and should be reserved for questions where you're at a complete loss for what to do. 

2) Cross-Hatching Bubbles

Cross-Hatching involves marking each bubble by either shading it diagonally or drawing a horizontal line through it. Again the idea is to make your mark ambiguous enough that the machine won’t be sure how to interpret it and will err on your side. Much like tampering with the black lines, this has a relatively low success rate. Cross-Hatching may provide you with a slightly higher chance of getting the correct answer as opposed to just bubbling a random answer. Don’t expect to get more than 20 to 25 percent success from adopting this strategy.

3) Light Shading

For any questions in doubt, simply fill in each of the answers with a very light shade of gray. The goal is to make it dark enough that it will still be read, but light enough the machine won't be sure what to do, and will become confused. This might cause the machine to skip over the question entirely, defaulting to a correct answer. This is an "iffy" method and involves guesswork in determining the right shade of gray to even give you a modest level of success. At best you can expect this to be right on par with the "Cross-Hatching" strategy.

These methods rely on tricking the machine and have a relatively low probability of working in your favor. In a worst case scenario your test will result in an error requiring manual grading from the teacher, and any sort of cross-hatching or shading will likely result in a simple "wrong" answer.

Not only will you probably get caught, but these methods don’t even work.

Taking things to an even more extreme level than merely trying to sneak past a couple tricky questions is the idea of gaming the entire test. There are a couple methods that have been reported to work, but they are actually urban legends (that will probably get you busted anyway).

1) Lip Balm the Margin

Somehow the rumor started a while back that you could game a Scantron Machine simply by taking Chapstick and smearing it along the left hand side of the sheet. The theory was the Chapstick would interfere with the scanning light and trick the machine into counting all of your answers as correct. Unfortunately, there is absolutely no merit to this, and the best case scenario it will result in is making your entire test ungradeable.

2) Use a Strip of Tape to Confuse the Scanner

This is a slightly more effective variation of the "urban legend" chapstick method. In this method, a strip of clear tape is placed alongside the black lines on the Scantron form and the reflection wreaks havoc on the scanning light, causing the machine to malfunction. Although there's not even a guarantee this will put the machine out of commission, you're once again faced with the problem of an outcome where at best you get no grade, and at worst you're failing the exam.

Either way, both of these attempts to game the system leave you without a score on your test, and probably don't end up doing you any favors with the teacher, either.

Given the low likelihood of gaming the system, it's time to employ some more basic tactics for besting a multiple choice test. The following three methods are typically your best options for when no amount of rereading the question is going to magically provide you with the answer.

1) Process of Elimination

If you can rule out any of the answers on multiple choice exams, your chances of making a correct guess are greatly increased. If any of the possible answers require considerable assumptions or are only true under very specific conditions you can most likely eliminate those from consideration. Once you've narrowed down your options then it's time to flip a coin and bubble in your answer.

2) Choose from the Middle

You may have heard "C" is the most common multiple choice answer, and there is actually some merit to that. If you are dealing with a four option multiple choice test, you will tend to score about 5 percent higher by randomly guessing "B" and "C" as opposed to "A" and "D". Unfortunately, this still leaves you with a grade somewhere in the neighborhood of 30 percent, and a definite fail. However, keeping this strategy in mind for select questions where you're forced to choose blindly can help boost your overall score.

3) Repose Each Question as True/False

If you don’t know the answer to the question, ask the question with each answer inserted as a statement.  If the sentence sounds right, then it probably is, if it sounds ridiculous, then cross it off and try the next.

4) Go with your "Gut"

Although it's hardly a substitute for actually knowing the answer, it has been shown that your gut or first instinct is often correct, and you can sometimes tap into correct information on a subconscious level. So, if you don't recall the answer but one of the choices just feels right, it's almost always worthwhile to stick to your guns and just mark it down without over thinking. But, it's probably not advisable to tackle an entire test on instinct alone.

Even if it might not be the most welcome piece of advice, there really isn't much of a substitute for actually knowing the material you're being tested on. You can definitely give yourself a small edge on multiple choice / scantron tests  by employing some of the basic tips, but if your plan is to try fool the machine, then you're probably heading for disappointment.

Even the best tested methods only work about 30% of the time, and you're still not accounting for the possibility that an instructor will notice your Scantron form doesn't mesh with the machine's results. It's hard to imagine a scenario where an extra 5 to 10 percent edge would justify the risks of being caught. If you really find yourself in a pinch and don't have a clue what any of the answers are you can always reach for your Chapstick (or prepare with it on your lips) and say a silent prayer that the urban legend just might work for you.