DAT common mistakes
DAT · Understand the traps and how to avoid them.
On organic chemistry items, memorises named reactions as isolated reagent-to-product pairs, then, when shown a substrate with an extra substituent or an unusual leaving group, picks whichever product 'looks like' the textbook example instead of working from the mechanism.
Most prep work rewards recall of canonical examples, so the student practises matching patterns rather than tracking electrons. Exam writers deliberately vary the substrate to test whether the underlying pattern is understood.
What to do instead
For every reaction you study, write a one-line mechanism (what attacks what, which bond breaks, where the electrons go). Before checking the answer, apply that one-liner to a deliberately altered substrate (added methyl group, changed leaving group) and predict the product yourself.
Spends the first 35-45 minutes of the natural sciences section grinding general chemistry calculation items, then has well under a minute per item for the remaining biology and organic chemistry questions and ends up guessing on content they actually know.
Calculation items feel productive and give a false sense of progress, and most students never rehearse section-level pacing under timed conditions, so they have no internal clock for when to bail out.
What to do instead
Use a strict two-pass strategy: on pass one, answer every recall-based item and flag any item that will need more than about 60-90 seconds of arithmetic. Only after the whole section has been swept do you return to flagged items with the time that remains.
Treats near-twin terminology as interchangeable and picks the answer choice containing the term that merely sounds right - osmolarity vs. tonicity, affinity vs. efficacy, reducing vs. nonreducing sugar, competitive vs. noncompetitive inhibition.
The words appear in the same chapters and often in the same sentences, so they get stored as a blurry cluster rather than as two distinct definitions with a distinguishing test.
What to do instead
For each confusable pair, write a single discriminating question you can ask yourself in the exam (e.g., 'Does the effect depend on solute concentration or on membrane permeability?'). Drill the pairs until you can answer that question in under five seconds.
Ranks angles by the overall visual 'size' of the drawn figures rather than by how wide the opening actually is, so a correct ranking is thrown off whenever one leg is drawn much longer than the other on the same or a neighbouring figure.
The visual system judges area and line length more readily than aperture, and the test deliberately draws unequal leg lengths to exploit exactly this.
What to do instead
Mentally re-draw each angle with both legs the same short length, or superimpose them in your mind with vertices together. Rank the two angles that look closest in size first and use the answer choices to eliminate, rather than trying to produce the full ordering in one pass.
In cube counting, recounts the same stack several times, loses the running total, and does not have a consistent rule for judging how many cubes must be hidden beneath an unseen position.
Counting is done by eye, sweeping the figure repeatedly, so the working memory load exceeds what can be held without a written tally.
What to do instead
Tally strictly once: record each column's height in a written list, then convert to counts of cubes with 0, 1, 2, 3, 4, and 5 painted faces in a fixed table. Answer only from the table, and never re-scan the figure from scratch.
On paper-folding items, unfolds the sheet in one motion and mirrors every hole across every crease at once, so holes end up on the wrong side of a fold or the layer multiplication is dropped.
The whole sequence is held in the head simultaneously, and each additional fold doubles the number of hole images to track, which reliably exceeds visual working memory beyond two folds.
What to do instead
Unfold one crease at a time, in reverse order, drawing the new holes for that single step on a sketched outline before moving to the next crease. Count layers explicitly at the moment of punching so the multiplication is never guessed.
On top-front-end items, matches the front view against the choices and selects the first option that agrees with it, without checking whether the top and end views could plausibly come from the same solid.
The front view is the most detailed and the most visually salient, so it feels like sufficient evidence, and cross-checking three projections is effortful.
What to do instead
Use a fixed checklist for every item: for each view, verify the outline, then the internal lines, then the position of every feature. Eliminate any choice where a single line or feature position is inconsistent across views before considering which looks 'closest'.
Reads each passage word-for-word from the start before looking at any question, then has to re-read large sections to answer specific items and runs out of time near the end of the section.
Full linear reading feels thorough and is what students did in undergraduate coursework, but the section tests locating and applying specific stated information under time pressure.
What to do instead
Preview the question stems first, then read the passage once at a fast skim while marking where each question's keyword appears. Answer by returning to the marked lines rather than re-reading the whole passage.
Selects a choice that is scientifically true and familiar from prior biology or chemistry coursework, even though the passage never states it - or that restates the passage's words while reversing the logical relationship described.
The passages deliberately overlap with prerequisite science knowledge, so outside facts feel safe, and a choice that sounds like the passage's own phrasing is hard to reject.
What to do instead
Before marking any answer, point to the specific sentence in the passage that supports it. If you cannot locate supporting text, eliminate the choice regardless of how true it is in general. For choices that echo passage wording, re-read the original sentence and check the direction of the relationship.
Performs exact long multiplication and division on every quantitative item, including setting up full fraction arithmetic, and reaches the end of the section with a dozen items unanswered.
No-calculator conditions trigger anxiety about precision, so students default to exact computation rather than trusting approximation, and they never practise estimation as a deliberate skill.
What to do instead
Before computing, round the numbers and estimate the answer's order of magnitude; then check which choices fall in that range. Use backsolving from the answer choices for algebraic items and dimensional analysis to eliminate choices with wrong units.
Solves correctly for the intermediate variable and stops - gives the son's age when the question asked for the father's, the discount amount when it asked for the final price, a rate when it asked for a time - and then finds that value among the answer choices.
The algebra becomes the focus of attention, and the target quantity is read once at the start and never re-checked. Test writers routinely place the intermediate value as a distractor.
What to do instead
Before starting the algebra, underline the exact quantity requested and write it as a label (e.g., 'final price = ?'). When you reach a number, restate it as a sentence with units before comparing it to the choices, and treat any choice equal to your intermediate value as a warning sign.