Almost every candidate meets the same moment on test day. You chose an answer a few items ago, moved on, and something now tells you it was wrong. Perhaps a later question reminded you of a rule you forgot, or perhaps it is just a vague unease. You can go back and change it, leave it alone, or spend the next two minutes half-thinking about it while working on something else — which is the worst of the three. Many people carry a piece of folk advice into the exam room: "always trust your first instinct." It sounds wise, and it is not a good rule. This article sets out a better one: when a change is worth making, when it is not, and how to practise the decision so it costs you seconds rather than minutes.
Why "trust your first instinct" is weaker than it sounds
The advice survives because of how memory works. When you change a right answer to a wrong one, it stings, and you remember it. When you change a wrong answer to a right one, you feel briefly pleased and forget it by the next item. Over a few years of exams, the painful cases pile up in memory while the useful ones quietly disappear, and "never change your answer" starts to feel like hard-won experience.
Research on multiple-choice testing has questioned this belief for a long time, and the general finding is that changes made for a reason tend to help rather than hurt. The important words are "for a reason." A first answer is not more trustworthy simply because it came first. It is a judgement made with whatever you had noticed at that moment. If you have since noticed something real, the second judgement is better informed, and refusing to act on it is not caution — it is ignoring evidence.
What the folk advice does get right is that some changes are not driven by evidence at all. They are driven by nerves. The task is to tell the two apart quickly.
A simple rule: change for a reason, not a feeling
Before you change any answer, ask yourself one question: can I name the specific thing that makes the new answer better?
If you can, change it. Good reasons are concrete. You misread a word in the stem — "not", "at least", "except". You find an arithmetic slip in your rough work. You notice that the rule you applied to a figure sequence fails on the third element. A later item reminded you of a relationship you had overlooked. Each of these is a fact you can point to, and our guide to using rough work effectively is largely about making those facts easy to find when you look back.
If you cannot name a reason — if the old answer just "feels wrong now", or the new one "looks more like the kind of thing they would ask" — leave it. That feeling is usually stress, not insight. Changing an answer on a feeling replaces one guess with another and spends time doing it.
One more case is worth separating out. If you look back and genuinely cannot decide between two remaining options, and your elimination was sound the first time, you are not in a better position than you were then. Leave the answer and move on. The method in our guide to process of elimination is what makes that first choice worth keeping.
Check how the format works before you plan around it
All of this assumes you can go back. Whether the dMAT lets you revisit and change items, and within which boundaries — per subtest, per section, or not at all once a section closes — is something to confirm in the official technical introduction and your participant portal rather than assume. Computer-based tests differ on this, and a review strategy built for a paper exam can quietly fall apart on screen if navigation works differently from what you expected. The syllabus overview sets out the structure of the modules; the official sources settle the navigation rules, and they take precedence over anything you read here.
If you can move back within a section, decide in advance how you will use that. If you cannot, the decision about each item has to be made before you leave it — which makes a calm, reason-based check before you click onwards even more valuable.
Don't let a doubtful answer follow you
The most expensive part of a doubtful answer is rarely the answer itself. It is the attention it steals from the items that come after. A candidate who keeps half a mind on a question three screens back is working at less than full capacity on the one in front of them.
If the format allows you to return, a practical habit is to deal with doubt in one deliberate pass rather than in scattered moments. When you feel uncertain about an item, make your best choice, note it on your scratch paper with a short reason ("check: units?"), and move on fully. If time remains at the end of the section, return to those notes in order and apply the rule above: a nameable reason means change, a feeling means leave. This fits naturally alongside the skip-and-return approach in our guide to pacing yourself under pressure.
If time does not remain, let the doubt go. One item is one item. Our guide to keeping time without a watch covers how to plan those closing minutes so you are not making these calls in a rush.
Practise the decision, not just the questions
You can find out whether your own changes help by tracking them. During timed practice, mark every answer you change and write a few words on why. When you review, sort those changes into three groups: wrong to right, right to wrong, and wrong to wrong. Then look at the reasons you gave. Most candidates find that their changes with a concrete reason worked out far more often than the ones made on a feeling — and that the feeling-driven ones cluster in the final minutes or after a hard item. That pattern is worth more than any general rule, because it is yours. Add it to your error log so it shapes your next practice set.
A full timed run on the free dMAT practice test is a good place to start collecting that evidence under realistic conditions.
On the day, keep it short enough to remember while nervous: change for a reason, leave it for a feeling, and do not carry doubt into the next question. That is a rule you can apply in a few seconds, and it is a better companion in the exam room than an old saying.
